SAN FRANCISCO — Andrew Luck faked out the defense, ran untouched into the end zone for a 6-yard touchdown and emphatically threw down the ball with a little extra oomph.
Even he thought it might be a career-best spike.
"It was nice to score," he said matter-of-factly of the moment.
Jim Harbaugh's former quarterback sure outplayed his current one, and it wasn't even close.
Luck passed for 164 yards while facing college coach Jim Harbaugh for the first time, and the Indianapolis Colts defeated the San Francisco 49ers 27-7 on Sunday.
Trent Richardson scored a 1-yard touchdown on his first carry in his Colts debut after being acquired on Wednesday from the Browns. He was drafted two spots behind top-pick Luck last year.
Ahmad Bradshaw added a 1-yard TD run in the final minutes, and Adam Vinatieri kicked a pair of field goals.
Luck kept coming through again to give Indianapolis (2-1) more opportunities.
"I know he's grinning from ear to ear," Colts coach Chuck Pagano said. "I've never seen him smile the way he was smiling after this one."
This marked Colin Kaepernick's first home loss at Candlestick Park as a starter.
Frank Gore ran for 82 yards after going for 60 total in his first two games, but there were few bright spots for Kaepernick as San Francisco (1-2) struggled to establish a passing game with tight end Vernon Davis sidelined by a hamstring injury. The defense committed numerous costly penalties for the third straight week.
Luck completed his initial six passes and spoiled the home team's reunion day between coaches on both sides who know each other's tendencies dating to their days at Stanford.
The Colts sure appeared to be better prepared.
Luck sent third-year coach Harbaugh to consecutive losses for the first time. He was happier about the fact his two sisters who attend Stanford got to see him play.