It's the longest winning streak for the Titans (6-3) since winning five straight in 2009, and it's their best start to a season since 2008 when the Titans last reached the playoffs as the AFC's No. 1 seed.
Murray ran for two touchdowns, and Mariota finished with 264 yards passing.
The Bengals (3-6) lost for the third time in four games despite sacking Mariota four times. They started with three defensive starters scratched and lost a fourth when linebacker Vontaze Burfict was ejected in the second quarter after pushing the arm of an official.
Cincinnati took its only lead at 20-17 on a 70-yard TD pass from Andy Dalton to A.J. Green with 5:03 left, but the Bengals couldn't stop the Titans, who drove 73 yards for the winning TD.
They had one last chance. On their final play, Dalton threw deep only to have Titans safety Kevin Byard knock the ball down.