PITTSBURGH -- The one thing the Jacksonville Jaguars have been able to count on all season is their defense.

Not on Sunday.

Instead, it was running back Leonard Fournette and quarterback Blake Bortles -- yes, Bortles -- who put the team on their backs and delivered a 45-42 AFC divisional playoff victory over the Pittsburgh Steelers at Heinz Field to send the Jaguars to the AFC Championship Game next Sunday in New England. This will be the Jaguars' third appearance in the AFC title game and first since the 1999 season.

"Usually during games we only ask the offense for like, 10 points, 13 points, and we try to carry the team the rest of the way and get the win," cornerback Jalen Ramsey said. "Today it wasn’t so much like that. We did hop up on them, and we kind of felt secure, so we started tripping, we started bulls---ing a little bit and let them get a couple plays, some deep balls, some little plays. And then we had to kind of lock back in and make sure we secured the win.

"The offense really held it down for us today, so shout out to them."

Bortles got off to a hot start but struggled for much of the second and third quarters. He found his rhythm on back-to-back drives in the fourth quarter, however, after the Steelers had twice cut the Jaguars' lead to seven. On the first drive, he completed 2-of-3 passes for 56 yards and a touchdown, including a 45-yard deep shot to Keelan Cole to the 3-yard line. Fournette then capped off the drive with a 3-yard touchdown run.

On the next drive, Bortles went 3-for-3 for 62 yards, including a 14-yard touchdown pass to fullback Tommy Bohanon that gave the Jaguars a 42-28 lead.

Bortles’ overall numbers weren’t impressive -- 14-for-26 for 214 yards -- but he didn’t turn the ball over, which was the most important thing the Jaguars needed out of him on the road in the biggest game of his career.

"All the guys that cover him know he's competitive as hell," coach Doug Marrone said. "He's doing everything he has to do. He was able to run today for yardage. he was able to throw the football and put us in good situations.

"... There are a lot of things going on in the game that he did a heck of a job with."

The Jaguars drafted Fournette last spring with days like Sunday in mind, and the rookie certainly validated their belief. He ran for 109 yards on 25 carries and scored three touchdowns -- runs of 1, 18 and 3 yards. Per Elias, that made Fournette just the second rookie in NFL postseason history with three rushing TDs in a single game. The other was William Floyd, who had three for San Francisco in the 1994 divisional playoffs against Chicago.

Fournette left the game midway through the second quarter with an ankle injury after having already rushed for 82 yards. He got treatment and returned for the second half, rotating with T.J. Yeldon. Fournette also helped seal the victory by gaining 9 yards on three plays to set up Josh Lambo’s 45-yard field goal with 1:50 to play to give Jacksonville a 10-point lead.

"You don't know what happens in playoff games," Fournette said. "They kept on fighting throughout the duration. We just knew every time they scored we had to come back and score. We needed to help our defense gather their breaths and just outscore them."

Bortles and Fournette helped make up for a Jaguars defense that gave up three touchdowns on fourth down -- including a 36-yard catch by Martavis Bryant late in the first half -- and 545 yards of total offense. That was a season high in total yards and passing yards allowed (462) by Jacksonville.

The Jaguars did, however, intercept Ben Roethlisberger once, and Yannick Ngakoue had a strip sack that Telvin Smith returned 50 yards for a touchdown.