Perhaps, playing on their home floor made the Celtics too comfortable. After all, they outscored the Heat three out of four quarters in Game 1's loss, despite missing two starters, then beat them 127-102 in the next matchup.
But on Saturday, the Heat came out with far more urgency, raised their level of physicality, and built a 39-18 lead entering the second quarter. While Boston got as close as being down a point in the final frame, 24 turnovers, many of them careless, stood in the way of earning a win.
Here's a deep dive into Miami's 109-103 victory to take a 2-1 lead in the Eastern Conference Finals.
Heat Throw the First Punch, Play with Far More Urgency than Celtics
Max Strus scored the game's first points, capitalizing on an open three in transition. Two possessions later, Bam Adebayo attacked off the dribble, earning two points at the rim. But Jaylen Brown responded with a mid-range pull-up jumper to get Boston on the board and make it 5-2.
On the Heat's following trip down the court, the Celtics left P.J. Tucker open, and he swished a three from the left corner. After that, Al Horford attacked out of the right corner, getting a layup that made it 8-4.
But Jimmy Butler leaked out on the basket, and Kyle Lowry found him for a layup. He also got fouled by Brown and converted on the free throw, extending Miami's early advantage to 11-4.
That prompted Ime Udoka to take a timeout. After the break, Tatum missed a floater in traffic, and Lowry buried a pull-up three. Butler then picked off a bad pass from Tatum, leading to an Adebayo jumper from 13-feet at the other end. That put the Heat ahead 16-4.
Adebayo knocked down a jump shot from 14-feet about a minute later to make it 18-6. After that, he scored on a reverse layup. And after Smart went 1/2 at the free-throw line, he hit another 14-foot jumper to give Miami a 22-7 lead. At that point, Adebayo was 5/6 with ten points.
And after Butler intercepted another ill-advised pass, this time from Horford, Adebayo fed Strus for a bucket from seven feet.
The only negative development to this point for the Heat, who built a 24-7 advantage with 5:28 left in the period, is Lowry headed to the locker room. Considering he missed the first two games of the series due to a hamstring injury that also cost him time in Miami's second-round matchup against the Sixers, perhaps that was their plan.
With just over 4:15 remaining, Horford swished a three from the left wing to make it 24-7. But Strus countered with a shot from beyond the arc to push the visitors advantage back to 17.
At the 3:01 mark, ESPN's Malika Andrews reported Lowry plans to periodically take trips to the back to keep his hamstring loose when he isn't in the game, confirming those earlier suspicions.
With 1:33 left, Brown pulled up and buried a jumper from just inside the arc in front of the right wing to cut Boston's deficit to 32-16. But Herro responded at the other end with a baseline jumper. Brown had an answer, hitting a turnaround jumper at the free-throw line.
With fewer than 20 seconds on the clock, Caleb Martin was the first one to an Adebayo miss, converting on the put-back and getting fouled. He also tacked on the free throw to make it 39-18 Miami.
That's where the score stood entering the second quarter. Credit the Heat. They dominated the first frame on the road in a place where that doesn't often happen. Adebayo was far more aggressive than the first two games, finishing the period with 12 points on 6/9 shooting.
As a team, Miami shot 64 percent from the field and 5/7 (71.4 percent) from beyond the arc. Conversely, Boston shot 27.8 percent, including 1/6 (16.7 percent) on threes. The Celtics also gave up four offensive rebounds and committed five turnovers, which the Heat turned into seven points.
Celtics Show Signs of Life Late in the Second Quarter
At the start of the second quarter, Martin broke free on a basket cut and got himself a dunk. Horford responded with a 12-foot floater from just inside the free-throw line to make it 41-20.
But Miami scored the following six points, including a Martin three from the left wing, pushing the visitors lead to 46-20 and causing a displeased coach Udoka to halt the action with 9:41 to play in the period.
After the break, the Celtics still didn't look comfortable against the Heat's zone defense, but Smart attacked a gap and banked in a floater from 14-feet while getting fouled. He then turned it into an old-fashion three-point play to make it 46-23.
Herro countered with a jumper from the right elbow. But after that, Horford, from deep in the paint, gave the ball to a cutting Tatum, set an excellent screen on Gabe Vincent, and Tatum finished over Adebayo. He also earned a trip to the line, where he cashed in on the free throw. That cut Boston's deficit to 48-26.
But at the other end, Adebayo found Tucker for an open three from the left corner. The following five points belonged to the Celtics as Smart hit a jumper from seven feet, and Pritchard swished a three from the left corner, making it 51-31.
After that, Pritchard got a stop against Butler, delighting the home crowd. But after grabbing the rebound, Smart had the ball stripped from behind by Lowry. It appeared like Boston again ended the possession, but the ball ultimately found its way to Butler under the basket, and he laid it in, while getting fouled. He added the extra point, making it 54-31 with just under seven minutes left.
Brown answered, driving from the right wing, finishing a layup on the left side of the rim. But Miami followed a Lowry high-arching jumper with an Adebayo dunk off a dish from Lowry, extending the Heat's lead to 58-35 with 3:17 remaining.
With 2:16 to go, Brown came off a screen from Horford, worked his way past Tucker and into the paint, and found a cutting Grant Williams, who came from the opposite corner. Williams got fouled by Strus, and appeared to hurt his shoulder on the play. Fortunately for him, Erik Spoelstra took a timeout after the whistle.
Following the break, Williams made both free throws to bring the score to 60-37. Then, after a Butler layup, Horford attacked a gap in the Heat's zone defense, producing a layup and a foul. He cashed in on the free throw, making it 62-40. It was as lively as the home crowd was to that point.
Tatum then euro-stepped his way to two points at the rim in transition. And after another stop, Horford cut for two points at the cup, finishing from slightly outside the restricted area. That cut the hosts deficit to 62-44 with 45.5 seconds on the clock.
Tatum closed out the half with a side-step three, lifting from the right corner to the right wing, making it 62-47, injecting energy into the crowd and giving the home team something to build off after the break.
Miami was shooting 51 percent from the field at the half, including 7/16 (43.8 percent) from beyond the arc. The Heat also produced 34 points in the paint and turned seven offensive rebounds into ten second-chance points.
With Lowry back in the lineup, they're playing faster and more decisively. That was most evident in transition, where they scored 16 points off 11 Boston turnovers and generated 13 on fast-break opportunities.
Adebayo led all scorers at intermission with 16 points. He also dished out six assists and grabbed four rebounds.
For the Celtics, Brown led the way with 15 points and four boards. Horford registered 12 points, eight rebounds, and three blocks. As a team, they shot 42.9 percent, including 3/12 (25 percent) on threes.
To come back and win this game, they'll need to take of the ball and play with far more physicality and connectivity on defense. The last few Miami possessions were the best Boston played defensively. Increased on-ball pressure played an important role; that needs to be the norm in the second half.
Heat Keep Celtics at Bay in Third Frame
The third quarter started with a curveball. After not playing in the first half, Victor Oladipo was in to start the second. According to Malika Andrews, Jimmy Butler is out the rest of the game due to right knee inflammation.
Brown sparked the second-half scoring, going strong to the basket for two points at the right side of the rim. That brought Boston within 13, making it 62-49.
But in a concerning moment, competing for an offensive rebound, Smart badly rolled his right ankle. He was down, screaming in pain and needed help getting to the locker room.
At the 10:25 mark, Lowry hit a three, but Brown countered with a layup, giving him 19 points and trimming the gap to 65-51. But then came an Adebayo layup, back-to-back turnovers by Brown, and another Adebayo layup after Miami couldn't capitalize on the first one. Adebayo's second basket made it 69-51.
The Celtics responded, though. Starting with Tatum finding Horford for a three from the right wing.
Tatum then went 1/2 at the foul line, and Brown got a layup, bringing the score to 69-57.
Max Strus answered with a three, but Horford then earned a trip to the line, where he knocked down both free throws. While he was at the charity stripe, the jumbotron showed Smart testing his leg. That sent the crowd into a frenzy.
Malika Andrews reported he had a quad strain. As badly as he rolled his ankle, fortunately, it apparently looked worse than it actually was.
Shortly after that, he was back in the game, getting the ball in the right corner after Tatum passed out of a double team. Oladipo sprinted back over to him, so Smart pump faked, then drilled a side-step three. That made it 72-62 as the TD Garden faithful roared. That caused coach Spoelstra to take a timeout.
With 5:08 remaining, Lowry swished a step-back jumper off the dribble, pushing Miami's lead to 74-62. But Boston countered as Brown attacked off the dribble, then swung the ball to Horford for a three from the right corner. That cut the deficit to 74-65.
Adebayo came up with a big play at the other end, grabbing a Herro miss, getting the put-back to go down, and getting fouled in the process. He also made the free throw, extending the Heat's advantage to 77-65.
Brown responded with a 15-foot pull-up jumper from the foul line. But after the Celtics' 17th turnover of the game and second in a row, Oladipo came off an Adebayo screen and hit a jump shot from ten feet while getting fouled. He tacked on the extra point, making it 80-69.
Brown answered, swishing a three from the right wing. But the Heat scored the following five points, including Tucker cashing in on an open three from the left corner to extend their lead to 85-70 with 1:22 to play.
On the Celtics' ensuing possession, Smart was there to clean up a missed three by Brown, bringing Boston within 13 again. Herro then knocked down a baseline jumper from just outside the paint. That made it 87-72 Miami entering the final frame.
The Celtics made a few runs, but the Heat constantly had an answer, preventing it from snowballing into the home team even threatening to take the lead.
Celtics' Comeback Falls Short
Adebayo started the fourth-quarter scoring, jab stepping his way to a mid-range jumper to push Miami's advantage to 89-72.
At the 9:34 mark, after a poor pass from Tatum right to Martin, Smart drew a charge, courtesy of an elbow to the face, denying the Heat more points in transition.
Gabe Vincent then got upset about a blocking foul on Dewayne Dedmon, feeling it should've been a charge on Brown. His displeasure earned him a technical. Tatum made the free throw, and Brown went 1/2.
After that, the Celtics swung the ball to Derrick White in the left corner, he attacked off the dribble, finding Tatum, and he kicked it out to Grant Williams for a three at the top of the key. That cut the gap to 89-80 with 8:52 to play, prompting coach Spoelstra to pause the action.
With 8:31 left, coach Udoka challenged a shooting foul against Williams. That proved wise as Williams hit the ball before Adebayo's hand, and the challenge was successful. The result was a jump ball at half court that Boston won. Nothing came of it, though.
At the 7:16 mark, a screen-and-roll produced a thunderous Adebayo dunk to make it 91-80. Then, Lowry lost the ball under the rim, but it slipped out of Williams' hands and into Tuckers, who hit a mid-range jumper as the shot clock expired.
But Smart countered, earning two points at the basket to make it 93-82 with 6:17 to go. Smart then drew a charge on Adebayo in the low post.
With just under 5:40 to play, Tatum hurt his right shoulder while trying to take Oladipo off the dribble. He stayed down as play carried on. After a Celtics full timeout, Tatum got helped to the locker room.
While he was down, Boston got two points, courtesy of Smart finding Brown for a layup. He also got fouled and capitalized on the free throw, making it 93-85.
Brown followed that up by charging downhill, maneuvered by Lowry, and hit a floater from about the semicircle below the free-throw line. Coach Spoelstra was upset about the lack of a foul call, feeling Brown elbowed Lowry on his way by him. Instead it was 93-87 with 4:54 left.
After a Miami timeout, Lowry lost the ball, and Williams secured it. At the other end, Brown stayed hot, knifing in for another layup to make it a four-point game with 4:14 to go.
As the Heat brought the ball up the court, Tatum returned to Boston's bench, which got the crowd to erupt. Shortly after that, he was back in the game.
Brown, absolutely on fire, then drilled a three from 26-feet out at the left wing. That made it 93-92.
But Strus responded with a clutch three to give Miami a 96-92 cushion with 2:16 remaining.
And after a shot-clock turnover by Boston, Adebayo buried a jumper from just inside the arc as the shot clock expired. That gave Miami a 98-92 advantage with 1:21 left.
The Celtics then committed yet another turnover, a bad pass from Tatum, forcing Williams to send Tucker to the free-throw line. He made both shots, putting the Heat ahead 100-92 with 1:07 to play.
Fighting for an offensive rebound, Williams earned a trip to the charity stripe, where he went 2/2, making it 100-94 with 1:01 on the game clock. But Boston then sent Oladipo to the line, where he went 1/2.
And as Smart tried to let the inbounds pass come to him, Lowry swooped in and stole it and found a streaking Strus for a layup that seemingly sealed the win. It gave the Heat a 103-94 advantage with 42.5 seconds remaining.
But the Celtics kept fighting. Brown swished a three from above the break, making it 103-97, prompting coach Spoelstra to take a timeout with 40.1 seconds left.
After the break, as Lowry inbounded from in front of Boston's bench, Smart fouled out, trying to draw an offensive foul on Tucker away from where the pass went. He also earned a technical for his frustration about the call and the lack of an offensive foul on Miami's first attempt to get the ball in.
Lowry capitalized on the technical, and Tucker made both free throws, extending the Heat's lead to 106-97 with 39.6 seconds remaining. Williams then hit a three with 31.3 seconds to play.
But he fouled out after that, picking up a flagrant-1 for hard contact with Oladipo while the latter was in the air, sending him into the seats. Oladipo went 1/2, Adebayo threw down a dunk, and Nik Stauskas splashed a three, making the final score 109-103 in favor of Miami.
The Heat were the more physical team, played with greater urgency and more discipline. And even without Butler, when the Celtics made runs, Miami responded, stemming the tide before losing the lead.
Adebayo, atoning for his lack of an impact the first two games, was the best player on the floor, finishing with a team-high 31 points on 15/22 shooting. He also grabbed ten rebounds, dished out six assists, and swiped four steals, at least tying for the team best in each category.
In the win, the Heat produced 48 points in the paint. They also feasted on turnovers. Boston coughed the ball up 24 times, leading to 33 points for Miami. Many of those were unforced errors. The Heat also generated 15 points on the fast break.
As for the Celtics, Brown paced them with a game-high 40 points on 14/20 shooting. Fourteen of those came in his fourth-quarter take over, scoring the most in the frame on either team. When Tatum returned to the bench, it's unrealistic to think Ime Udoka would hold him out, but Boston's offense quickly lost its rhythm after he came back in.
Brown produced nine of his 40 points at the free-throw line, attempting 12 foul shots. Compare that to Smart and Oladipo tying for the second-most by taking five free throws.
Brown also grabbed nine rebounds, but he committed a game-high seven turnovers. Him losing the ball off the dribble, sometimes without getting stripped, is a concerning theme. One wonders if it's related to a wrist injury.
As for Tatum, he turned in one of his worst playoff games of his career. He finished with ten points on 3/14 shooting, including 1/7 on threes. He never seemed comfortable. And while some shots went in-and-out, he didn't deal well with the physicality of the Heat's defense on Saturday. He also coughed the ball up six times, including some careless passes.
Boston didn't just squander a 40-piece from Brown; it also wasted a terrific performance by Horford. The veteran big man registered 20 points, 14 rebounds, three assists, and three blocks.
As a team, the Celtics shot 48.6 percent from the field and went 12/32 (37.5 percent) on threes. They went 23/30 (76.7 percent) at the free-throw line compared to Miami going 12/14 (85.7 percent). One didn't have to wait until post-game to see the Heat's displeasure about that disparity.
And Boston didn't just shoot well and more than double Miami's free-throw attempts; the Celtics also turned nine offensive rebounds into 21-second chance points. Taking better care of the ball likely would've swung Saturday's outcome.
Game 4 of this Eastern Conference Finals series between the Celtics and Heat is Monday night at 8:30 ET. Inside The Celtics will have content related to the game coming out before, during, and after. And follow @BobbyKrivitsky on Twitter for updates and analysis from pregame to post.