Tennessee went on to with 22-21.
Mariota appeared to lose the ball when he was drilled on a sack by Derrick Johnson, but the officials ruled he had been stopped by forward progress, which is not reviewable.
The Chiefs, who won their final four games of the regular season to clinch their second straight AFC West title, took a 7-0 lead in the first quarter on a 1-yard run by National Football League rushing champ Kareem Hunt.
After the Titans' Ryan Succop put Tennessee on the board with a 49-yard field goal, the Chiefs drove 79 yards in 1:52 to make it 21-3 on a 14-yard Smith pass to Demarcus Robinson. But the Titans switched seamlessly to Henry, who gained 156 yards on 23 carries, including a 35-yard touchdown run.
"I don't really have anything good to say", Chiefs coach Andy Reid said, "so I'm just going to kind of stay away from any comments on those guys". They've won four straight games, while the Titans have lost three of their last four.
Alex Smith connected with tight end Travis Kelce for a 13-yard touchdown pass with 2:15 left in the first quarter.
But on third-and-6, he scrambled left before firing a pass into the end zone, where it was deflected into the air by Chiefs cornerback Darrelle Revis.
Kelce was knocked out of the game in the second period with a concussion, following an ugly head-to-head collision with a Tennessee defender. For the second year in a row, the Titans held the Chiefs offense to zero points scored in the second half of a game.
The Titans drove into Chiefs territory midway through the second quarter but Peters intercepted an underthrown pass from Mariota in the red zone, ending the threat.
But replay showed Henry was clearly down by contact.
Kelce didn't return to the game and the Chiefs struggled offensively in the second half.
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