KANSAS CITY, Mo. -- The kids grew up on Saturday. A new era of Tennessee Titans football started, one that enjoys playoff success and sports a refuse-to-lose mentality.

The Titans erased a 21-3 Kansas City Chiefs lead behind their two young offensive stars in Marcus Mariota and Derrick Henry to score the franchise's first playoff win since 2003.

This week was full of questions for the Titans, ranging from coach Mike Mularkey's job security to Mariota's guts to pull this type of victory off. They answered them all, scoring 19 unanswered points in the second half to earn a thrilling 22-21 comeback victory.

Henry promised to be motivated after what he called a "soft" Week 17 performance against the Jaguars. There was nothing soft about how Henry played Saturday, rushing for 156 yards and a touchdown on 23 carries.

"That was his big coming out party," left tackle Taylor Lewan said. "If he runs like that, we're going to be ight."

Henry is just the third player in Titans/Oilers history to rush for 100 yards in a playoff game. Eddie George did it twice, Earl Campbell once. That's good company, and Henry looked just like them on Saturday. There should now be little question as to who the Titans' running back of the future and now should be.

Mariota's legs took center stage in the second half, as he kept plays alive by scrambling to find downfield receivers and running when there was an open lane. He had five rushes for 52 yards before three kneel-downs. He threw two touchdown passes, even one to himself -- a pass that was headed into the end zone from the Chiefs' 6 was batted by Darrelle Revis and into the hands of Mariota, who dived in for a third-quarter score.

"He can run. He can pass. He can block," Henry said of Mariota. "He can catch, too."

And it was only right that the play to cap it all was Mariota delivering a perfect lead block for Henry to get the final first down on a third-and-10 play with under two minutes remaining.

The Titans are now 2-14 in the Mariota era when trailing by 14-plus points, with both wins coming against the Chiefs. This also was Mariota’s fifth fourth-quarter or overtime comeback of the season, most in the NFL.

The Titans became the fourth team to overcome at least an 18-point halftime deficit to win a postgame game. The last was by the Patriots in Super Bowl LI, which also had a 21-3 halftime score.

Going seven-for-seven on third downs in the second half outside of kneel downs and riding Henry despite a big deficit played a huge role in this comeback.

The Titans have consistently shown heart and fight this season, even when everything wasn't clicking on all cylinders. That's what showed up at Arrowhead Stadium when they were the more focused and clutch team Saturday.

The game winner came when Mariota delivered a golden rope to Eric Decker on a skinny post for the go-ahead 22-yard touchdown. It was redemption for Decker, who had a drop on a third-down play earlier in the game.

“Guys didn’t blink an eye,” Mariota said. "Through the ups, the downs, the energy it doesn't change."

Dick LeBeau's defense deserves a lot of credit for shutting down the Chiefs after a rough first half in which quarterback Alex Smith threw for 231 yards and two touchdowns. Not having to face star tight end Travis Kelce, who missed all of the second half after suffering a concussion in the second quarter, made things a little easier, but there were clear adjustments and huge individual plays made.

Safety Johnathan Cyprien made two huge stops to squash the Chiefs' final comeback drive. The Titans also held the NFL's leading rusher, Kareem Hunt, to 42 rushing yards.

The Titans will now head to Pittsburgh or New England for their divisional-round contest.

"We can play with anybody on any Sunday, Saturday," tight end Delanie Walker said. "We're ready for them."