Indianapolis Colts running back Marlon Mack scores a touchdown on an 8-yard run ahead of Tennessee Titans free safety Kevin Byard in the second half of Sunday night's game in Nashville.

NASHVILLE — The Indianapolis Colts have Andrew Luck healthy and throwing the ball all over the field.

That was more than enough with an injured Marcus Mariota stuck watching from the Tennessee Titans' sideline.

Luck passed for 285 yards and three touchdowns as the Colts beat the Titans 33-17 Sunday night for the final spot in the NFL playoffs as the AFC's No. 6 seed.

With the Houston Texans winning the AFC South title earlier Sunday with a victory over the Jacksonville Jaguars, that left the Colts and Titans playing for the second wild-card berth and a visit to Houston this Saturday.

"It's been a lot of fun," Luck said. "It's been a journey, that's for sure. I think what this team is doing is enjoying the journey."

Luck remained perfect against Tennessee, notching his 11th victory in as many starts against the AFC South rival. He helped the Colts (10-6) — under first-year coach Frank Reich — end their postseason drought by winning for the ninth time in 10 games after a 1-5 start.

The Titans (9-7) had won four in a row, but with Mariota sidelined by neck and foot injuries, they missed securing a second straight playoff berth for the franchise in Mike Vrabel's first season as coach.

"We made a decision that Marcus wasn't going to play tonight," said Vrabel, who gave no details on when the decision not to start Mariota was made nor the seriousness of his injury. "We'll continue to evaluate him and try to worry about his health and every one of those guys' health — Marcus included."

The Colts intercepted two of Blaine Gabbert's passes in the final 9:05 to finish off their 13th win in the past 15 games in the series.

Marlon Mack ran for 119 yards and a touchdown for the Colts and Adam Vinatieri kicked field goals of 53 and 25 yards, though NFL's oldest active player missed his final extra-point attempt in the game.

Derrick Henry, who took the Titans' first offensive snap out of the wildcat formation, rushed for 93 yards.

Tennessee was missing three defensive starters ,with four-time Pro Bowl tackle Jurrell Casey placed on injured reserve last Monday and linebacker Brian Orakpo scratched for a third straight game. That left the Titans unable to pressure Luck, even with the Colts missing center Ryan Kelly because of a neck injury.

And Luck simply shredded a Tennessee defense that came in as the NFL's No. 2 scoring defense, having given up an average of just 18 points a game, and sixth against the pass.

Luck drove the Colts 92 yards before hitting Dontrelle Inman with an 11-yard touchdown pass and finished off a 90-play drive that used up nearly 10 minutes with a 9-yard pass to Eric Ebron. That left the Colts up 14-0, having held the ball for nearly 17 of the first 21 minutes.

Luck also added a 1-yard touchdown toss to Ryan Hewitt on the opening drive of the third quarter for a 24-10 lead.

"The most satisfying thing is to walk in the locker room, look at your teammate and say, 'We did it,' and we did it," Reich said. "Those are three of the best words that you can ever say to your teammate. To me, that's really the pot of gold at the end of the rainbow."

Titans linebacker Jayon Brown almost singlehandedly kept the Colts from putting the game away before halftime when he returned an interception 22 yards for a touchdown in the second quarter. After the Titans Adoree' Jackson inexplicably grabbed at a bouncing punt that put the Colts at the Tennessee 9, the Colts had a touchdown run by Mack erased because of a holding penalty on center Evan Boehm.

Two plays later, Brown stripped Mack of the ball and recovered it.

Ryan Succop kicked a 38-yard field goal that pulled Tennessee to 17-10 at halftime. Gabbert threw a 22-yard touchdown pass to Luke Stocker to pull the Titans to 24-17 late in the third quarter.