Luck was 18 of 23 for 178 yards with two touchdown passes, but earned his eighth career fourth-quarter comeback by scrambling for a score with 5:20 to go in the game.
It was Indianapolis' first opening-day win since 2009.
But he also threw two interceptions in the red zone, the second coming with 25 seconds left in the game to seal Indy's victory.
Luck led the Colts to TD drives on their first two possessions, but didn't score again until Luck's go-ahead score.
Copyright 2013 by The Associated Press