Andrew Luck threw for 222 yards and two touchdowns and the Indianapolis Colts denied a late Houston rally Saturday to beat the Texans 21-7 in an NFL playoff opener.

Colts rusher Marlon Mack carried 24 times for 148 yards and a touchdown, the first 100-yard run performance allowed by Houston all season, and bottom seed Indianapolis advanced to an American Conference semi-final next Saturday at the top seed Kansas City Chiefs.

"We get another one next week and that excites me," Luck said. "It'll be fun. That's a great team. It should be a great game."

Luck, who completed 19 of 32 passes, opened the scoring with a 6-yard touchdown toss to Eric Ebron and then marched Indianapolis 74 yards in nine plays on a drive capped by Mack's 2-yard touchdown run as the Colts took a 14-0 lead in the first quarter.

"We were on the details," Luck said. "We played disciplined. We made plays. Thankfully 21 was enough the way our defense played. What a great team victory. I'm proud of the guys.

"Our guys up front just kept plugging away and Marlon took a couple of those and just shimmied and to finish it out that way was really great."

Houston's Deshaun Watson threw his first interception in 215 passes to Colts defender Kenny Moore but Luck was picked off by Brandon Dunn to end the Indy threat.

On the next Colts' possession, Luck moved the visitors 65 yards and connected with Dontrelle Inman on an 18-yard touchdown pass for a 21-0 Indianapolis advantage.

The Texans could not cut into the Colts' edge before half-time, losing the ball on downs at Indy's 9-yard line on their last first-half march.

Houston finally cracked the Colts' defense with 10:57 remaining in the fourth quarter as Watson flipped a 6-yard touchdown pass to rookie Keke Coutee, capping a 16-play, 89-yard march that lasted 6:13.

Watson kept Houston's next drive going with a dramatic 21-yard fourth-down run but the Texans turned over the ball on an incomplete fourth-down pass at the Colts 24-yard line and Indianapolis ran out the clock to secure a 10th victory in 11 games.

"Dominate up front -- that's the way you win playoff football on the road," Colts coach Frank Reich said. "We're not done yet. We're writing our story. We know we've got one more stroke of the pen. There's something about believing in each other. No one is stopping us."

The Colts became only the third NFL team to start 1-5 and reach the playoffs, going 9-1 to close the regular season, while the Texans were the first NFL playoff team in 20 years to start the NFL season 0-3.