Andrew Luck threw for 222 yards and two touchdowns in the Colts' wild card win over the Texans. (Mark J. Rebilas/USA TODAY Sports)

Before Saturday’s AFC wild card game, Indianapolis wide receiver T.Y. Hilton said Houston’s NRG Stadium felt like a “second home,” because of how well he and the Colts’ offense have played there.

And on Saturday — a 21-7 Indianapolis win over the Houston Texans — the Colts settled in pretty quickly. Indianapolis romped to 75-yard scoring drives on its first two possessions and left Houston, the winner of nine straight games after an 0-3 start, in the dust. It was thanks to heady play from quarterback Andrew Luck, a sturdy offensive line and a defensive performance that should make next week’s opponent, the Kansas City Chiefs, a bit uneasy.

Here are the three biggest takeaways from Indianapolis’s 21-7 win:

That Colts defense is the real deal

Now winners of five straight games and 10 of their last 11, the Colts defense proved it can stop a team with bona-fide weapons. Consider that Houston wideout DeAndre Hopkins, lauded by many as the NFL’s best pass-catcher, finished with 37 yards on five receptions.

Facing a dual-threat quarterback (as they will next week in the Chiefs’ Patrick Mahomes), the Colts never let Houston’s Deshaun Watson get comfortable in the pocket, even when Indianapolis rushed four and dropped seven. On Watson’s first interception, the Colts rushed three and used a spy. Cornerback Kenny Moore II stepped in front of Houston’s tight end near the first down marker, and it appeared as though Watson never saw him.

Watson was the Texans’ only effective rusher, and he called his own number strictly out of necessity. Tailbacks Lamar Miller, Alfred Blue and D’Onta Foreman combined for 29 yards on eight carries.

Indianapolis won on third down

Well, either the Colts won on third down, or the Texans folded big time. Indianapolis converted its first six third-down attempts. Three of them came on the first two drives. Luck and Hilton were in sync from the game’s very first possession.

Facing third-and-12 at the Colts' 23 yard-line to open the game, Luck found Hilton in a tight window against man-to-man coverage. To keep the drive alive on third-and-2 from the Colts’ 43 yard-line, Luck escaped the pocket, then dropped an easy pass to Hilton, who ran for 13 yards. Two plays later, he found Hilton behind the secondary for a 38-yard chunk that set up the Colts with first-and-goal.

Here’s another crucial reception from Hilton on third down that helped Indianapolis run out the clock.

Indianapolis did not go three-and-out until the second drive of the third quarter. Overall, the Colts converted 9 of 14 third downs, the Texans just 3 of 13.

Houston has some decisions to make this offseason

The Texans enter the offseason with a couple of pretty significant roster questions. Defensive end Jadeveon Clowney and safety Tyrann Mathieu are free agents, and Houston is expected to have $67.3 million in cap space, the sixth-most in the NFL, per spotrac.com. That already leaves significant money available to sign an offensive lineman or two, and Houston can also add to that unit through the draft.

“Because of the Texans’ problems on the offensive line, they are put in a tough spot if they ask Deshaun Watson to drop back 40 times a game and bring the team back from two or more scores,” NFL analyst John Clayton wrote for The Washington Post on Monday.

A revamped group protecting Watson will help Houston avoid that nightmare scenario, which played out Saturday.

Key plays:

The Colts' defense holds: Indianapolis forced another turnover on downs with 4:09 to play, pressuring Deshaun Watson and disrupting his pass that was intended for Vyncint Smith. After the Texans finally scored in the fourth quarter, their defense was able to force Indianapolis to punt. But Houston still needed more urgency on its next drive, which went 65 yards in 11 plays.

Colts stuff Texans again on fourth down: Houston drove 64 yards in 11 plays but came up short at the 9-yard line with 1:24 to play in the half. The Texans' possession looked promising — with the offense clicking for the first time all afternoon — but Deshaun Watson’s pass for DeAndre Hopkins was low and wide. After the play, Hopkins was seen walking into the tunnel with team trainers instead of joining the offense on the bench.

Colts score again: Andrew Luck has been on fire in the first half. He found wide receiver Dontrelle Inman for an 18-yard score with 6:24 in the second quarter, putting Indianapolis ahead, 21-0.

Luck has thrown for 175 yards and two touchdowns on 14-of-18 passing, evenly distributing the ball to five different targets. The Colts are perfect in five attempts on third down, too. The Texans, meanwhile, have allowed 242 yards of offense and have yet to break 100 themselves. (Colts 21, Texans 0, 6:24 2nd Quarter)

Healthy dose of Marlon Mack puts Colts up big: Indianapolis’s offense has been too much for Houston to handle early on. In another surgical drive, the Colts marched 74 yards in nine plays, including Mack’s two-yard touchdown run.

The Colts’ offensive line paved the way for 52 yards on the ground in the drive, and Indianapolis already 145 yards of total offense. (Colts 14, Texans 0, 5:25 1st Quarter)

Colts strike first: Andrew Luck hit Eric Ebron for a six-yard score on the Colts’ opening drive, and Indianapolis took a 7-0 lead with 10:35 to go in the first quarter.

Luck started hot, connecting on 5 of 7 attempts on an nine-play, 75-yard drive. The Texans defense struggled on the opening drive on third down. Luck hit T.Y. Hilton on third and 12 three plays into the game. Then to cross the 50 yard-line, the pair connected again after J.J. Watt jumped offside when the Texans looked like they had Indianapolis stopped.

Luck found Hilton again over the middle for 38 yards that set up the touchdown pass to Ebron. Adam Vinatieri converted the extra point. (Colts 7, Texans 0, 10:35 1st Quarter)

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