If you're still of the belief that Smith is due to regress or that this San Francisco team cannot win consistently with him at the helm, it's time to give it up. With Sunday night's 19-of-30 passing performance, Smith has now gone 216 passes without throwing an interception.
That number is no coincidence -- the 49ers' game plan, under Jim Harbaugh, asks Smith to do just enough to win, without often putting him in a position to fail. Which brings us back to that game-clinching touchdown drive against Detroit.
First, Smith faced a 3rd-and-7 from his own 24 and dumped one down to Michael Crabtree, who caught it just shy of the marker and pushed ahead for the first down. Three plays later, it was 3rd-and-14, and the Lions dropped deep, daring Smith to throw into coverage. So instead, the 49ers called a pass for Crabtree over the middle and he, with Frank Gore and Mario Manningham blocking in front of him, rolled for the first down.
Smith found Crabtree again on a 3rd-and-9 in Detroit territory, as Crabtree just sat down shy of the first down, then fell across the spot. The long, grueling drive culminated with Smith hitting Vernon Davis for a TD, moments after Smith scrambled for a first down and came up bleeding profusely from the nose.
"Michael made me look good tonight," Smith told NBC's Michelle Tafoya after San Francisco's 27-19 win. "He made a bunch of catches. I really feel like, as a quarterback, you're a reflection of the guys around you -- and the guys around me made me look good."
The Lions had chance after chance to get San Francisco off the field. The 49ers simply stayed one step ahead of the Detroit defense, all night long.
"We're really just making plays," Crabtree said. "We can go far, as long as Alex trusts us, which he's doing."
The biggest reason that Harbaugh can play it fairly close to the vest with his veteran QB is that he knows he has one of the game's best defenses to fall back on. The 49ers shut down Aaron Rodgers and the Packers in Week 1, then turned around and did the same to Matthew Stafford on Sunday night.
Stafford finished with 230 yards through the air, but he was stuck in double digits until the fourth quarter. And even though the Lions won the time-of-possession battle (30:26 to 29:34) and ventured inside the San Francisco 30 on six different occasions, the 49ers held their ground.
Detroit had to settle for five Jason Hanson field-goal attempts (he made four) and one late touchdown, after the game had been more or less decided.
"We were just able to hold up a little bit on them," Justin Smith told Tafoya, "and it was a heck of a team win."
The 49ers' No. 1 focus on defense -- as is the case for most teams that play the Lions -- was to limit Calvin Johnson. San Francisco sent double-coverage Johnson's way almost all night, with a cornerback defending him tight and a safety helping over the top. Johnson still hauled in eight passes for 94 yards, but the 49ers did not let him get deep and, as a result, took away Stafford's favorite weapon.
Detroit tried to counter by running the football, but it was a futile effort.
"They were taking the approach of playing deep safeties and taking away the big play, which they were able to do," Lions coach Jim Schwartz said in his postgame press conference. "When people do that, you need to hurt them underneath and hurt them with the run.
"We didn't do a good enough job in any phase, whether it was the run game, the pass game, defense, special teams ... we left a lot of opportunities on the field."
That's really the M.O. of the 49ers: to frustrate the opposition. What you see is what you get with this 49ers team, and it is what makes it so hard to play against them.
They're a throwback outfit in that regard. While offenses around the league are spreading their formations out more and more, and adding in some unique looks with their quarterbacks, the 49ers just line 'em up and come right at you.
San Francisco takes the same approach on defense. Sunday night against Detroit, the 49ers rushed four and dropped seven, for the most part. There were some openings out there to be had (and ones that the Lions will regret missing), but nothing game-changing.
To win a game against Harbaugh's 49ers, a team really has to go out and dictate the tempo and the flow. Not often -- the NFC title game and Kyle Williams' fumbles aside -- will this group beat itself.
Smith is the poster child for that approach. Before Harbaugh arrived, he was a quarterback who played haphazardly and without much confidence. Now, he's one of the leaders of this team and a guy that loves having the ball in his hands down the stretch.
What changed? Well, the expectations from San Francisco's coaching staff, for starters. Harbaugh has kept Smith within himself and put him in position to succeed. He has responded extremely well to that missive, and the 49ers are growing ever tougher as a result.