INDIANAPOLIS – With everything on the line, it was a matter of trust.

Trust in the veteran quarterback to make the necessary throw to complete yet another game-winning drive.

Trust in the rookie receiver to make the highlight catch with every set of eyes at Lucas Oil Stadium and one-on-coverage pressing him down the right sideline.

Trust in Frank Reich’s aggressive play call on 3rd-and-13 from the Jacksonville 32-yard line with 23 seconds remaining, the Indianapolis Colts trailing 27-26 and the season once again slip, slip, slipping away.

Trust.

“Frank went into the headset and said, ‘Trust what you see,’’’ Matt Ryan said.

Just like that: Colts 34, Jaguars 27.

Once Ryan saw the Jaguars’ defensive approach on the game’s most consequential down – cornerback Shaquill Griffin up close and pressing on the right side – he trusted his rookie wideout to make a play that added momentum to the Colts’ season.

He trusted Alec Pierce.

“I was thinking ‘Go win the game’ when you get that look,’’ Ryan said. “We had stuff on the other side if we had a different look . . . but we got the look we wanted and I really think in those situations, you trust your instincts, trust your gut, trust your guys and try to go win the game.’’

His trust in Pierce was reinforced when Pierce shed Griffin’s pressure at the line of scrimmage, got a step on him down the right sideline and ran under Ryan’s perfectly-placed pass for a 32-yard touchdown with 17 seconds remaining.

“I’m proud of Alec for making that play,’’ Ryan said.

It was Pierce’s first career touchdown, and atoned for dropping a sure TD in the end zone in the opener at Houston. Ryan never hesitated at targeting Pierce with so much on the line.

“Making the plays helps,’’ he said of his growing trust in Pierce. “It certainly helps when you see guys being productive.’’

Pierce described the game-winner as “a pretty simple play,’’ and unfolded exactly as the Colts had hoped.

“It was press,’’ he said. “I think we were kind of hoping they were going to be up there loading the box, trying to get a sack and bring pressure. They knew they had to get us out of field goal range.

“They did exactly what we were hoping for. They gave that press, one-on-one coverage to my side. He gave me a chance. They have a ton of trust in Matt. They know he’s going to make a throw where he’s not going to throw an interception in that situation.

“It’s going to be our-guy, no-guy. He gave me a chance and I’m grateful the coaches believed in me.’’

Instead of falling further behind the 3-2 and idle Tennessee Titans in the AFC South, the Colts moved to 3-2-1 – that’s their record, not a countdown – with next Sunday’s rematch with the Titans in Nashville looming.

So much went into a dramatic Sunday at Lucas Oil Stadium.

The defense did just enough despite yielding 243 rushing yards – the most against the Colts since 2014 – and its two longest runs of the season: JaMycal Hasty’s 61-yard touchdown and Travis Etienne Jr.’s 48-yarder. Trevor Lawrence was 20-of-22 for an economical 163 yards, but he was sacked four times and the Colts added nine tackles for loss, including two from safety Rodney McLeod.

Offensively, Reich and his staff had been kicking around the idea of going no-huddle for the past few weeks, and earmarked the rematch with the Jaguars for implementation.

“Matt handled it perfectly,’’ Reich said.

Without top running backs Jonathan Taylor (concussion) and Nyheim Hines (concussion), the Colts opted for a hurry-up, pass-heavy game plan. They finished with 45 yards on 16 carries – Deon Jackson had 42 yards on 12 attempts before exiting the game late with a quadriceps injury – and essentially put the game in Ryan’s hands.

“Matt had an incredible day,’’ Reich said.

Ryan entered the game as the NFL’s most sacked (21) and error-prone (10 turnovers) quarterback. He was hit six times – including on the game-winning TD to Pierce – but not sacked. And the Colts were turnover-free for the first time.

“The o-line was special,’’ Reich said. “That was an unbelievable performance.’’

Ryan finished 42-of-58 for 389 yards, touchdowns to Pierce, rookie tight end Jelani Woods (10 yards) and Parris Campbell (4 yards). The 42 completions were a franchise record and personal best. The 58 attempts were Ryan’s most since a career-high 61 at Arizona in 2013.

To appreciate the enormity of Ryan’s afternoon, consider he delivered the 45th game-winning drive of his 15-year career. Twice, in fact.

His 10-yard TD to Woods early the fourth quarter gave the Colts their first lead of the game at 26-21, but Jacksonville countered with a mammoth 18-play 84-yard drive that consumed 10 minutes, 3 seconds and finally ended with Lawrence’s 4-yard toss to Christian Kirk.

Less than 3 minutes remained. Initially, Reich trusted Ryan to deliver if for no other reason than he had done so throughout his career. This season, Ryan had generated game-winning drives against Kansas City and in overtime last week at Denver, and put the Colts in position to win in overtime at Houston before they settled for a tie when Rodrigo Blankenship missed a 42-yard field goal.

“Again and again,’’ Reich said. “He’s unflappable and wants the ball in his hands. He’s at his best, makes his best decisions.

“He’s done that for 15 years. There’s something wired in his DNA that’s just different.’’

With the game hanging in the balance, the Colts trusted Ryan to do it again. And in the end, Ryan trusted Pierce.

Ryan’s 4-yard hookup with Michael Pittman Jr. on 3rd-and-4 at the Indy 40 – Pittman took a massive hit from safety Rayshawn Jenkins – gave the final drive life, as did a 15-yard Ryan-to-Pittman completion on 3rd-and-10 with 42 seconds remaining.

After Ryan lost 4 yards when his feet got tangled up with center Ryan Kelly’s and Phillip Lindsay gained 1 one, the Colts faced a 3rd-and-13 at the Jaguars 32.

Twenty-three seconds remained, and Reich sent in a play that included a “conversion’’ route for Pierce. If Griffin pressed Pierce at the line, Pierce converted his route to a ‘go.’

Pierce’s eyes widened when he saw Griffin pressing at the line of scrimmage. It was going to be him versus the cornerback.

“That’s my favorite part of football right there,’’ he said. “One-on-one and solo receiving. I just love it.’’

Pierce finished with three catches for 49 yards, and pushed his season totals to 18 receptions and 271 yards. Everything has come in the last four games after he was shut out in the opener and missed the first Jacksonville game with a concussion.

“I trusted Alec,’’ Ryan said. “He’s so good on those kind of routes. A lot of things in those situations, throwing the ball past the sticks, being aggressive, taking a shot is huge. You can’t play scared in those situations.

“I thought it was a great call, great route. I just tried to give him a chance and a really good play by him.’’

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You can follow Mike Chappell on Twitter at @mchappell51.