Rookie T.Y. Hilton and Luck connected on a 61-yard touchdown pass just before halftime.
Watt's forced fumble on Mewelde Moore on the Houston 1 was recovered by Tim Dobbins early in the second quarter, robbing the Colts of points. And the Colts stalled inside the red zone again and had to settle for Adam Vinatieri's 26-yard field goal to cut Houston's lead to 10-3.
The Texans had set the tone as they got to Luck early, sacking him twice on the Colts' second drive. Antonio Smith got to him first, and Watt put a move on backup tackle Jeff Linkenbach and took him down for a 15-yard loss.
On offense, Johnson was dominant. He put Houston up 10-0 when he waltzed into the end zone for a 3-yard touchdown reception. Johnson kept things going earlier in the drive when he caught a pass, lost it and then grabbed it again just before it touched the ground for a 10-yard gain on third-and-9.
NOTES: Luck needs 74 yards to break Cam Newton's rookie yards passing record of 4,051 yards. ... Dobbins has recovered four fumbles this season, a franchise record. ... Braman's two blocked punts this season are a single-season franchise record.