James scored a layup and flexed.
He and the Cavaliers finally bullied one of the NBA's big boys.
James scored 29 points - and overcame an early wardrobe malfunction - and Kevin Love and Kyrie Irving added 21 apiece and Cleveland got its first win this season over an elite team by beating the San Antonio Spurs 117-103 on Saturday night.
The Cavs won their fourth straight under new coach Tyronn Lue, who was promoted after David Blatt was fired on Jan. 22. Cleveland came in 0-5 against San Antonio, Golden State and Chicago, three top-tier teams who figure to contend with them for a title this season.
Lue has the Cavs playing at a faster pace and the Spurs, who were again without center Tim Duncan, couldn't keep up with them.
''The Big 3 came through for us,'' Lue said. ''It gives us confidence to know that we can beat a great team like the San Spurs.''
Cleveland's 117 were the second-most given up this season by San Antonio, which came in allowing a league-best 90.6 points per game. The Cavs had more than that after three quarters.
''They pushed the ball,'' said Spurs guard Tony Parker, who finished with 13 points. ''They were still a very good team before. It's one of those games where our defense just wasn't there. We made too many mistakes and against a good team you can't do that.''
Irving (10) and Matthew Dellavedova (8) scored Cleveland's first 18 points in the fourth quarter. James scored the next three when he blasted through Mills, who was no match for the 6-foot-8, 250-pound James.
In just a week, the Cavs have been transformed under Lue, who has encouraged James to make plays for his teammates and Irving to attack the basket.
''We definitely played good basketball tonight on both sides of the floor,'' James said. ''We pushed the tempo offensively and did everything coach wanted us to do against a great team.''
Down by 17 points at the half, the Spurs scored the first eight of the third quarter, a spurt that prompted an oh-no-here-they-come vibe through Cleveland's loud crowd, which was in playoff form.
But the Cavs responded with a flurry that showcased their offensive depth. Love and Dellavedova hit 3-pointers and James powered inside for several baskets, helping Cleveland push its lead to 88-69 late in the third. James scored 16 in the quarter.
James, too, made one of his signature defensive plays by chasing down Spurs guard Manu Ginobili on a breakaway and blocking his shot at the rim.
Love scored 18 points in the first half, when the Cavs opened a 17-point lead and gave the Spurs their glimpse of their new, fast-paced offense.
Without Duncan and with Aldridge on the bench after picking up three quick fouls in the first quarter, the Cavs had nothing to stop them inside and were able to do what they pleased.
Locker-room attendants inadvertently put out the wrong shorts for James, who came out in the first quarter wearing different ones than his teammates. They had on gold bottoms with wine and white stripes up the sides. His were plain.
Everything else about the Cavs was perfectly in order.
Cleveland scored 37 points in the first quarter, which ended with J.R. Smith dropping a contested jumper from just inside the 3-point line.
James didn't know he had on the wrong shorts until someone told him during a timeout in the first quarter.
''I never realized it, I mean yellow top, yellow bottom,'' he said. ''I know we have a couple different yellow uniforms now so I'll be checking them from now on.''
Spurs: San Antonio entered the night with a 12 1/2-game lead in the Southwest Division, the club's largest since 2004. ... Leonard, who will make his first All-Star game appearance next month, joined Michael Jordan and Hakeem Olajuwon as the only players in league history to be named an All-Star, Finals MVP and Defensive Player of the Year. ... David West, signed in the offseason to provide frontcourt depth, started for Duncan and scored 8.
Cavaliers: Dellavedova finished with 15 points. ... Cleveland improved to 19-3 at home, best in the Eastern Conference. ... James played in his 662nd game for Cleveland, moving him past the late John ''Hot Rod Williams'' and into fourth place on the team's career list. ... Browns owners Jimmy and Dee Haslam and Indians manager Terry Francona were among those in attendance.
Spurs: Host Orlando on Monday.
Cavaliers: Visit Indiana on Monday.