JACKSONVILLE -- Ben Roethlisberger finally slew the Jacksonville dragon with his hard-nosed play.

To cap a brilliant fourth quarter, Roethlisberger stretched the nose of the football across the goal line on a diving 1-yard touchdown run with three seconds left as the Pittsburgh Steelers shocked the Jaguars 20-16 on Sunday.

After a rough three quarters that featured three Roethlisberger turnovers, the Steelers' offense was unbelievable on two scoring drives spanning 148 yards to clinch the victory.

Roethlisberger conceded he played a "horrible game."

"Pretty special ending, though," he said with a smile.

Teammates were calling his touchdown something else.

"Legendary," guard Ramon Foster said.

The image of Roethlisberger diving to shake a Myles Jack tackling attempt provides the perfect snapshot for the Steelers' gutsy six-game winning streak, fueling a serious playoff push.

The winning score was a shovel option play, and Roethlisberger was the last option. But he didn’t see anyone open as he rolled to his right, so he ran for it, knowing the Steelers had one timeout left.

"Oh boy," right tackle Matt Feiler recalled saying to himself when Roethlisberger started to dive in his direction. "It was exciting. He’s a playmaker."

That timeout was saved from the Steelers' previous defensive series, when, inside the two-minute drill, Pittsburgh stuffed Jacksonville’s third-and-5 rushing attempt.

How Roethlisberger got a 300-yard game out of this is unreal. Through the first 44 minutes, he had 66 yards and three interceptions on 11-of-24 passing. He ended it with 314 yards and two touchdowns -- a 78-yard bomb to Antonio Brown late in the third quarter and a beautiful back-of-the-end-zone strike to a leaping Vance McDonald for 11 yards.

As Jacksonville built a 16-0 lead, Roethlisberger and the Steelers appeared to be navigating through quicksand for much of what was a very winnable game.

Turns out it was.

"That’s the thing about this group -- we’re going to fight till the end," Roethlisberger said. "And we literally fought till the end."

That doesn’t change the fact that Jacksonville controlled the pace with rangy defenders and a stout running game. But Pittsburgh was at its gutsy best late.

After committing seven turnovers in two matchups against Jacksonville last year, Roethlisberger entered this matchup as one of the league’s hottest quarterbacks, armed with motivation to quiet Jaguars cornerback Jalen Ramsey, who called him "decent at best" in the offseason.

There’s something about the presence of Ramsey and the Jags' defense that makes Roethlisberger look indecisive at times. That’s been the case over the past two regular-season matchups (including Sunday's win), with Roethlisberger and Brown trying the same slant routes, and Ramsey making the same play for an interception over the top -- one of two picks for Ramsey in the game. In his past two regular-season games against Jacksonville, Roethlisberger has one touchdown and six interceptions when targeting Brown. The offense converted one of its first nine third downs and got in scoring range for the first time thanks to two Jacksonville penalties. James Conner also had two bad drops.

Somehow, the Steelers overcame all of that. JuJu Smith-Schuster and Brown each had 100-yard games, making key catches in the fourth quarter, and Roethlisberger found his rhythm late. Roethlisberger credited Smith-Schuster’s ability to win outside after the offense decided to move him around the formation late in the game. He finished with eight catches for 104 yards and was "kind of a hero," Roethlisberger said.

Both sides of the ball knew they needed each other.

"We’ve got too much to play for," Foster said.

The defense had two goals: stop the run, and don’t let quarterback Blake Bortles get out on bootlegs.

They definitely stopped Bortles, who was sacked six times and finished with 104 passing yards. But that first goal wasn’t looking so good when the Jaguars went for 141 first-half rushing yards, controlling the clock for 23 of the first 30 minutes of the game.

After halftime the Steelers tightened up and held Jacksonville to 28 yards rushing on 17 second-half attempts. Jacksonville got the ball with 2:22 left and gave it back with 1:42 left because the defense walled off three straight runs.

And the Steelers won in ugly fashion, just the way defensive end Cam Heyward likes it.

"To call it a steal is a disservice to the guys in this locker room. We battled, and we took it," Heyward said. "It was a brawl out there. I’m not going to sugarcoat it."