A year ago at this time Andrew Luck was at home struggling with an injured shoulder that cost him the entire season.

On Saturday he wrote a happy ending to the latest chapter of his comeback season, throwing for 222 yards and two touchdowns and the Indianapolis Colts raced out to a big lead and cruised to a 21-7 win over the Houston Texans in the wild-card game.

Luck put on a show in his hometown in a stadium where he'd attended games throughout childhood and played in them since high school, throwing for 191 yards and two touchdowns before halftime to help the Colts (11-6) build a 21-0 lead.

He denied feeling "at home" at NRG Stadium, but admitted to having warm feelings for the city he grew up in and where his grandparents and many friends still reside.

"But it's still an away stadium," he said. "It was very loud, very energetic, but fun to win, certainly."

Running back Marlon Mack had 148 yards and a touchdown for Indianapolis, which advances to face the top-seeded Kansas City Chiefs in the divisional round next weekend.

"We know we have an elite quarterback and we can throw it for 400 and win when we have to," Indianapolis coach Frank Reich said.

"But the margin for error in playoff football when you try to do it that way is very thin. When you can win like this — running the football and stopping it — that's just everything."

Houston (11-6), which overcame a 0-3 start to win the AFC South, gave up too many big plays and couldn't get anything going on offense in the first half to fall into the huge hole.

Deshaun Watson, who was sacked an NFL-leading 62 times in the regular season, was sacked three times and hit eight more times in a disappointing playoff debut. He finished with 235 yards passing with a touchdown and an interception.

"Just a lack of execution on our part," Watson said. "We didn't make plays. I didn't make plays. Communication was a little off. You just got to give the Colts the credit."

The Colts, who opened the season 1-5, continued an impressive run by winning their fifth straight and for the 10th time in 11 games. Saturday was their first playoff appearance since the AFC championship game loss at New England in the "Deflategate" game in the 2014 season.

It was another good game in a splendid season for Luck. He threw for 4,593 yards and 39 touchdowns in the regular season after missing all of 2017 with a shoulder injury.

The Texans didn't score until rookie Keke Coutee grabbed a 6-yard touchdown pass to cap a 16-play, 89-yard drive that included a fourth-down conversion that cut it to 21-7 with about 11 minutes left.

They led the NFL with nine comeback wins this season, but their attempt at a rally ended on their next possession when Watson's pass on fourth-and-10 from the Indianapolis 24 fell short with about four minutes left.

Luck threw for 863 yards with six touchdowns as the teams split two meetings in the regular season. He picked up right where he left off in this one, when he found Eric Ebron on a 6-yard TD pass on their first drive. That play was set up by a 38-yard catch by T.Y. Hilton, who had 63 yards receiving on that drive.

"We didn't have a lot of guys that made the playoffs so the guys that made the playoffs wanted to go out there and set the tone early, try to get the crowd out of the game," Hilton said. "That's what we did."

Hilton didn't have any catches on the next drive, but the Colts still drove down the field easily and made it 14-0 on a 2-yard run by Mack later in the first.

Houston went for it on fourth-and-4 from the Indianapolis 45 on its second possession and Watson was intercepted by Kenny Moore II. It was his first interception since he threw two against the Redskins on Nov. 18.

The Colts got to the 17 after that before J.J. Watt deflected Luck's pass and he was intercepted by Brandon Dunn. But the Texans couldn't move the ball and had to punt.

Indianapolis pushed the lead to 21-0 when Luck connected with Dontrelle Inman on an 18-yard touchdown pass in the second quarter.

"It's very frustrating when they're able to execute and get their job done," Watt said. "We had a couple of big penalties early in the game as well. But you have to overcome it and you have to find a way to win."

The Texans had a fourth-and-1 from the 9 late in the second quarter and went for it again instead of settling for a field goal. The gamble didn't pay off when Watson's pass to DeAndre Hopkins was low and bounced in front of him in the end zone.