"I wasn't caught up in, 'Oh my gosh, I'm 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."
Before Sunday, Harbaugh was 7-0 following a defeat — and Harbaugh faced criticism for playing and starting Aldon Smith two days after the linebacker was arrested and jailed on suspicion of driving under the influence and marijuana possession.
49ers CEO Jed York said after the game Smith would seek treatment and miss Thursday's game at St. Louis and perhaps be away from the team longer. Smith apologized to "everybody I let down" while acknowledging he has a problem and will fix it.
Kaepernick had been 4-0 on his home field since becoming a starter last November. This time, his 49ers were 10½-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.
"There's no one thing, we just didn't execute this offense," Kaepernick said.
The 49ers had six penalties for 48 yards and didn't 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 Bradshaw's 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.
On the Colts' first play from scrimmage, safety Donte Whitner received a 15-yard unnecessary roughness penalty when he led with his helmet on a hit against Bradshaw after a 3-yard catch. Tarell Brown was flagged for pass interference on the next play.