PITTSBURGH (AP) The Jacksonville Jaguars spent the first month of the season looking equal parts awesome and awful, taking one step toward respectability immediately followed by a baffling step back.

On the road facing a team expected to play deep into January and perhaps beyond, the Jaguars instead served notice their best start in nearly a decade is hardly a fluke.

Turns out, running back Leonard Fournette can fly in more ways than one. And a secondary getting better by the week appears ready to make the Jaguars a legitimate threat in the underwhelming AFC South.

Fournette soared for a 2-yard touchdown and sprinted 90 yards for another, and Jacksonville used Pick 6s on back-to-back Pittsburgh drives to stun the Steelers 30-9 on Sunday.

''I think this is a completely different ballclub compared to last year,'' said Jaguars safety Tashaun Gipson, who had two of Jacksonville's five interceptions. ''We got guys who will make plays on the football, guys in situations to make plays, and that's all you can ask for. This year has been fun so far.''

And decidedly different. The Jaguars (3-2) have already matched their 2016 win total and are above .500 after five games for the first time since 2010 thanks in large part to Fournette's precocious play.

The rookie finished with a season-high 181 yards, the knockout punch delivered with his dash to the open end of Heinz Field with 1:47 to go that sent whatever portion remained heading for the exits following Pittsburgh's worst home loss in coach Mike Tomlin's 11 seasons.

''They drafted me for a reason,'' Fournette said, adding later his only goal on the third-longest touchdown run ever against the Steelers was simply to not get caught.

No chance.

Fournette and Jacksonville's defense were so dominant that quarterback Blake Bortles only attempted one pass in the second half. The way the Jaguars were overwhelming Steelers quarterback Ben Roethlisberger, Bortles didn't have to do much other than watch Fournette go to work.

Pittsburgh (3-2) again struggled to get big-play production out of an offense that was supposed to be among the league's best. Five games in, the Steelers look average. Roethlisberger completed 33 of 55 for 312 yards and his career-high five interceptions, the most by a Steelers quarterback since Mark Malone threw five against Cleveland in 1987.

''You know it's one of those things where I've been doing this a long time,'' Roethlisberger said. ''I've had bad games before, bad stretches. I've had good ones too. You just find a way to move on and play better.''

A week after a sideline outburst generated headlines and drew Roethlisberger's ire, Steelers wide receiver Antonio Brown caught 10 passes for 157 yards. Brown didn't score, but twice men attempting to cover him did.

The Steelers led 9-7 in the third quarter when Roethlisberger looked left for Brown. Jacksonville defensive lineman Abry Jones tipped it into the hands of Telvin Smith, who chugged 28 yards to put Jacksonville in front with 6:38 left in the period.

The Jaguars defense struck again on Pittsburgh's next series. Roethlisberger tried to hit Brown down the sideline. Jalen Ramsey deflected it, Barry Church came down with it and 51 yards later Jacksonville had turned a two-point deficit into an 11-point lead without taking an offensive snap.

''I was just right there in the nick of time to grab it,'' Church said. ''I wasn't letting anybody tackle me before I got to the end zone. I had to get there.''

When Gipson made a leaping pick near the Jacksonville goal line in the final minutes to thwart any chance of a Pittsburgh rally, it gave the Jaguars 15 takeaways on the season. They managed an NFL-low 13 while going 3-13 in 2016.

SUPERMAN

Fournette gave the Jaguars an early lead with a spectacular 2-yard touchdown dive in the second quarter. The former LSU star basically jumped from the 4 and flew untouched over the line of scrimmage into the end zone. Not bad for a 240-pound back known more for his heft than his hops.

''I noticed the line knocked everybody down,'' Fournette said. ''I jumped 5 yards. I was nowhere near the goal line. I jumped 5 yards back and I made it. I surprised myself.''

QUOTABLE

''It was a (butt) whooping, plain and simple.''

Steelers wide receiver Martavis Bryant, who was held to 21 yards receiving on five receptions.

GROUND TO A HALT

Jacksonville came in with the top-ranked pass defense in the league, though that number was a bit of a misnomer. The Jaguars also came in last in rushing yards allowed, giving up an average of 165 per game. Pittsburgh managed just 70 on 20 carries, with Le'Veon Bell mustering just 47.

''They stopped the run,'' Steelers tackle Alejandro Villanueva said. ''They pretty much forced us to throw the entire game and they played better than us at the end.''

UP NEXT

Jaguars: Host the Los Angeles Rams next Sunday.

Steelers: Travel to Kansas City next week in a rematch of last year's AFC Divisional Round playoff. Pittsburgh edged the Chiefs 15-13 to reach the AFC title game.

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This story has been corrected to show that the final score was 30-9.

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