It came on a record-setting day a the kickoff temperature of 23 degrees and a wind chill of 16 degrees set the record for the coldest game in Nissan Stadium history.
The Titans (9-7) will travel to Kansas City (10-6) to take on the Chiefs on Saturday at 3:35 p.m.
The Titans secured their first playoff appearance in nine years.
The Jaguars (10-6) enter the playoffs with two straight losses, their first losing streak of the year.
Tennessee entered with three straight losses but never trailed.
A Jaguars defense that save for a 66-yard screen pass touchdown by Derrick Henry played solid the entire game, needed one more third down stop to give the offense a final chance.
Marcus Mariota would not let it happen, though.
The Titans secured the win when Mariota scrambled for 13 yards to convert a third-and-6. He got away from defensive end Calais Campbell and then stiff-armed strong safety Barry Church to gain extra yardage as the clock wound down to the two-minute warning.
When the Jaguars got possession back, they were out of timeouts and had only 18 seconds remaining. Starting at their 18, quarterback Blake Bortles' first-down pass by intercepted by safety Kevin Byard.
Like he said early in the week, Jaguars coach Doug Marrone played his starters the entire game except for injured left tackle Cam Robinson (abdomen) and nose tackle Abry Jones (back).
Playing in frigid conditions–- the 23-degree kickoff temperature was tied for the fifth-coldest in Jaguars history and was the chilliest in Nissan Stadium history – the teams played to scoreless first quarter tie.
Titans tailback Derrick Henry made it 6-0 with a 66-yard touchdown catch. He caught the screen and turned up the field, breaking tackle attempts by cornerback A.J. Bouye and nose tackle Eli Ankou. Henry, the Yulee native starting for an injured DeMarco Murray, posted his first NFL touchdown catch.
Telvin Smith blocked the Titans' extra point attempt.
The Jaguars' offense started punt-punt-punt but cut the lead to 6-3 on Josh Lambo's 41-yard field goal with 10:14 left in the first half. The key plays were an 18-yard catch by Allen Hurns (on third-and-7) and a 23-yard screen catch by Leonard Fournette.
Two turnovers helped Tennessee take a 12-3 lead into halftime.
First turnover: Punt returner Jaydon Mickens called a fair catch but the football hit him as he was trying to block a Titans' player. Ryan Succop cashed in with a 25-yard field goal.
Second turnover: Receiver Keelan Cole fumbled with 1:07 left in the half. The Titans took over at the Jaguars' 29 and got a 39-yard Succop field goal.
The lead became 15-3 with 7:42 left in the third quarter on Succop's 38-yard field goal, set up by a Mickens' muffed punt and bad Jaguars field position.
The Jaguars trailed by 12 points entering the fourth quarter, but then got hope thanks to a Titans mix-up.
On a second down play from the Jaguars 26, Mariota and Henry collided during the exchange and Yannick Ngakoue scooped it up and returned it 67 yards for the touchdown, cutting Tennessee's lead to 15-12 with 10:48 remaining. It was Ngakoue's first career touchdown and the Jaguars' seventh defensive touchdown this year.
The Titans went three-and-out and the Jaguars suddenly had a chance to take the lead. But after a 16-yard catch by Fournette to start the drive, the Jaguars gained four yards on the next three plays and punted.
The Jaguars went three-and-out after taking over with 5:01 remaining.
Tennessee kept possession with three minutes remaining when Mariota gained 7 yards to convert a second-and-6. Three plays later, Mariota converted the aforementioned third-and-6 with a 13-yard scramble.
— Ryan O'Halloran, The Florida Times-Union