Smith was ghastly in a 37-yard first half, but was re-animated for a two-touchdown, 159-yard second half to lead the 49ers to a 24-16 win over the Denver Broncos in London.
Frank Gore ran for 118 yards and a touchdown, but it was Troy Smith's unexpected poise under pressure in the fourth quarter that made this one memorable.
Smith directed traffic in the middle of a pass rush and completed a miraculous 38-yarder to Delanie Walker where he surely couldn't even see where he was throwing.
On the Niners' next possession, he found Michael Crabtree wide open for a 28-yard touchdown.
Vernon Davis had to leave the game after re-spraining his ankle late in a comatose first half that saw but one 49ers field goal and punts on all five Denver possessions.
Still, compared to a soccer game, 3-0 is an enormous amount of scoring in the first half!
But the Broncos blew it open when Kyle Orton dropped a 71-yard bomb to Brandon Lloyd in the third quarter, and a game official did more to keep Lloyd from scoring than did 49ers safety Taylor Mays. That nutty new Denver Bronco wildcat option Tim Tebow converted the touchdown on a one-yard run to make it 7-3.
It should have been 14-3 Broncos. Orton and Knowshon Moreno executed a perfect flea-flicker and long pass for a touchdown, but Denver was called unfairly for a chop-block.
It's appropriate for phantom calls help your team on Halloween! But the Broncos still made it 10-3 on that third quarter drive with an eventual Matt Prater 32-yard field goal.
But Troy Smith's two fourth quarter scoring drives turned the tide decisively not only for the game, but for the 49ers' season as well. This team could still technically contend in the NFC West.
Frank Gore added the insurance touchdown after Manny Lawson stripped Kyle Orton with 7:18 left in the game.
The Broncos missed an extra point with 2:22 remaining, and then had a punt return for a touchdown called back less than a minute later. Love playing against your special teams, Broncos.
So now the 49ers have a third-string quarterback who has fantastically outplayed both his first- and second-string counterparts.
And suddenly, Mike Singletary's substitution moves are almost as popular as Bruce Bochy's.
Joe Kukura is a freelance writer whose Brian Wilson Halloween costume is being understood by absolutely no one in London.