INDIANAPOLIS — Andrew Luck started Sunday by carving up Jacksonville’s staunch defense.

• Leonard Fournette returned for his first game since Week 4 and scored twice
• Blake Bortles threw for 319 yards and two touchdowns
• The Jaguars' drive to tie the game or take the lead was stopped by a fumble

He finished it by playing the eager spectator.

After throwing three first-half touchdown passes and picking up only two first downs in the second half, he celebrated when the Indianapolis Colts’ defense delivered the decisive turnover with 90 seconds left to preserve a 29-26 victory over the Jaguars.

“We played well enough in the first half to put some points on the board,” Luck said. “Then we survived.”

Barely survived, that is.

Trailing by three, Jacksonville quickly marched from its 42-yard line into field goal range, and when Rashad Greene Sr. went down at the Colts’ 23, it looked like the Jaguars were already set up for at least a tying field goal. Initially, Greene was ruled down before the ball squirted out.

But just before the Jags (3-6) ran the next play, the whistles blew for a booth review. A few minutes later, the call was overturned, giving the ball and the game to the Colts, who have won three straight for the first time in three years.

“I thought we got the play off, but obviously, we didn’t,” Jags coach Doug Marrone said before elaborating later. “Personally, I thought it wasn’t a fumble. But I see what everybody sees from the sideline.”

Last year’s AFC runner-ups were a popular preseason pick to dethrone New England. Instead, the Jags have lost five straight, six of seven and are last in the division.

And they don’t get more painful than this.

Jacksonville had an extra point blocked and nearly returned for a 2-point conversion in the first half.

Two 15-yard penalties helped Indy score its fourth touchdown, a 1-yard pass from Luck to Mo Alie-Cox late in the second quarter. An offside call on the ensuing extra point prompted coach Frank Reich to go for two, which Marlon Mack punched it in to make it 29-13.

Jacksonville kicker Josh Lambo missed his first field goal of the season, a 52-yarder, wide left in the third quarter but then made a 55-yarder to cut the deficit to three with 4:03 left.

Finally, Kenny Moore III sealed the Jags’ fate by ripping the ball away from Greene just before his leg went down and Malik Hooker scooped it up.

“Offensively we’re looking to improve, put that thing away,” Reich said. “But make no mistake about it: This was a huge win for us.”

Luck started fast, hooking up with Eric Ebron on a 53-yard TD pass seven plays into the game.

After Donte Moncrief tied it on an 80-yard scoring play, Ebron answered with a 2-yard TD run to make it 14-7. Luck connected with Ebron again on a 12-yard TD pass, giving the tight end a career-high third score with 9:19 left in the first half.

Luck finished 21 of 29 with 285 yards, one interception and was not sacked. He has three TD passes or more in six straight games, one of three QBs to do so in a single season. His company: Peyton Manning and Tom Brady.

Blake Bortles was 26 of 38 with 320 yards and two TD passes while Leonard Fournette had 53 yards rushing, 56 yards receiving and his first two scores of the season — one on the ground, one through the air.

It just wasn’t enough.

“It’s a good defense, a lot of respect for that defense,” Luck said. “We certainly weren’t sharp enough.”