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.
Jim Harbaughs former quarterback sure outplayed his current one, and it wasnt 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 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 hes grinning from ear to ear, Colts coach Chuck Pagano said. Ive never seen him smile the way he was smiling after this one.
This marked Colin Kaepernicks his first 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 teams reunion day between coaches on both sides who know each others 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.
I wasnt caught up in, Oh my gosh, Im going up against Coach Harbaugh, (Greg) Roman and (Vic) Fangio, Luck said. I figured any time you play this sport, coaches and players come and go so much that you always end up going against someone that you played for or played with or had a good relationship with.
Kaepernick had been 4-0 on his home field since becoming a starter last November. This time, his 49ers were 10 1/2 -point favorites but looked nothing like the better team in getting thoroughly outplayed.
He completed 2 of his 8 first-half passes and wound up just 13 for 27 for 150 yards with an interception and three sacks.
Theres no one thing, we just didnt execute this offense, Kaepernick said.
The 49ers had six penalties for 48 yards and didnt look much better than they did in their five-turnover, 29-3 loss at division rival Seattle last week.
Kendall Hunter ran for a 13-yard score late in the first quarter, but San Francisco has scored 10 total points the past two games.
Richardson carried 13 times for 35 yards, giving the Colts quite the 1-2 punch with Bradshaws 19 rushes for 95 yards.
Luck took advantage of a pair of penalties by San Francisco to open Indianapolis seven-play, 80-yard scoring drive over the opening 3:40 for a 7-0 lead.
Luck kept drives going with clutch plays as the Colts won the third straight meeting with San Francisco.
On third-and-9 and throwing from near his end zone late in the third, Luck hit Reggie Wayne for a 25-yard gain in which Wayne broke through several tacklers.
All-Pro linebacker Patrick Willis went down on the play and was helped off the field moments later with a groin injury that sidelined him for the rest of the game.
The Colts busted through San Franciscos defensive line, which lost nose tackle Ian Williams to a season-ending ankle injury last week.
Its one of those games you look back on down the road and say, This was a signature win, maybe one that helped you to do great things, that helped you accomplish the program you built, Pagano said.