INDIANAPOLIS — If the present showed us anything, it’s that there’s promise in the future.

Just as Anthony Richardson, and a stubborn defense, had the Indianapolis Colts in position to pull an upset of the Jacksonville Jaguars Sunday at Lucas Oil Stadium. The Colts were up 21-17 deep into the fourth quarter, and there’s every indication the franchise is walking confidently into a bright tomorrow with their rookie quarterback leading the way.

“He did great. I felt like he was solid, like all day,’’ veteran wide receiver Michael Pittman Jr. said. “Nothing really rattled him. He was just the same guy from play 1 to play 60 or whatever it was.

“It didn’t happen the way we wanted it to happen, but we have something we can build off of.’’

AFC South-favorite Jacksonville kept the Colts winless in their last 10 season-opening games — 0-9-1, if you’re keeping track — by erupting for two touchdowns in a span of one minute and six seconds late in the fourth quarter.

The Colts went from leading, 21-17, with 6 minutes to play, to dealing with a 31-21 loss in the blink of an eye.

But before the late fade, they were right there.

“We definitely were in position,’’ Richardson said. “We had it the whole way, I believe.’’

Credit Gus Bradley’s defense. Through three quarters, it limited Jacksonville to 243 yards on 50 plays and had two takeaways — Tony Brown’s interception and a wacky 26-yard fumble return for a touchdown by DeForest Buckner.

“They played lights out,’’ Richardson said.

And credit the undeniable presence of Richardson.

He was the Colts’ youngest rookie quarterback to start a game — 21 years, 111 days — and the third-youngest in the NFL since 1970.

Yet two, three, four times Pittman mentioned Richardson’s poise.

First-year coach Shane Steichen was equally as impressed despite the unsatisfactory bottom line.

“I thought he played solid, I did,’’ he said.

Steichen shouldered the blame for Richardson’s lone interception. Two plays after Jacksonville eased back into a 24-21 lead, Richardson’s pass to the left sideline intended for tight end Kylen Granson was snatched by cornerback Tyson Campbell.

“We trust that play a lot,’’ Richardson said. “I saw the corner, but I just threw it a little too flat.’’

Let’s call it a rookie mistake.

But again, that happens. Colt rookie quarterbacks now are 1-6 in season-openers for a reason. George Shaw (1955) is the aberration.

On the grand scale, Richardson did his part. He completed 24-of-37 passes for 223 yards with the one interception and his first NFL TD, a 39-yard catch-and-run by Pittman. Richardson also was the leading rusher of an otherwise ineffective ground attack with 40 yards and a 2-yard TD on 10 attempts. He was sacked four times, but none were the result of protection breakdowns.

In keeping with Sunday’s historical backdrop, Richardson became the Colts’ first rookie quarterback to notch a passing and rushing TD in a season opener.

“I thought he managed the game well,’’ Steichen said. “Thought he did some really good things, really encouraged with his progress and what he did.’’

On the downside, Richardson was unable to prod the offense when it mattered most. The Colts converted just 2-of-12 times on third down and were 1-of-5 on fourth down. Richardson suffered incompletions on two fourth-down attempts and was stuffed for no gain on a fourth-and-1 sneak at the Jacksonville 16 following Brown’s interception.

“I’ve just got to help the team,’’ he said. “Going into the game, we knew we were going to be aggressive when it came down to the conversion downs. We just got to find a way to convert; stop getting penalties.’’

One of Richardson’s more encouraging moments came late after Jacksonville had placed a hammerlock on the game. Down 31-21 with four minutes to play, he was the catalyst on a 17-play drive that reached the Jaguars 1-yard line. Richardson completed 7-of-10 passes for 59 yards and scrambled three times for 12 yards.

He was unable to finish the drive after being shaken up on a big hit by Josh Allen and Andre Cisco at the 1. Gardner Minshew II replaced Richardson, and the drive stalled three plays later.

The sight of Richardson on the turf for several seconds produced a collective unease throughout Lucas Oil Stadium.

“I’m more so hurt that we lost than my knee,’’ he said.

Richardson appeared to injure his left knee and began limping noticeably early on a 12-yard run in the first quarter. He said he banged the knee into the turf.

“Other than that,’’ he said, “I’m good.

“Just a little bruise on it. A little ice, and I’ll be back.’’

That’s what this season and the coming years are all about — Richardson dealing with the good and the bad, and progressing through it.

After the game, Richardson and Trevor Lawrence exchanged words on the field. Lawrence has felt the weight of a franchise on his shoulders similar to Richardson. The Jaguars took him with the No. 1 overall pick in 2021.

“Yeah, I thought he made some great plays,’’ Lawrence said. “Obviously, being a rookie quarterback, it’s a tough spot. There’s a lot of learning that you have to do, and it’s just every week, learning and getting better.

“The only thing I told him after the game was ‘Great game.’ He made some unbelievable plays, but ‘Just try to protect yourself.’ The hits add up in this league, and they are a little different than in college. So, I told him to protect himself.

“I’m excited to watch his career unfold. I think he’s going to be a great player.’’

Sunday was step one, and it was a huge one. What was the biggest lesson Richardson took away from his first NFL start?

“How different it is from college,’’ he said. “Every possession matters, every down matters, every play matters. You can’t just take off one play because you think it’s all right. You can’t take off one quarter because you think you’ve got the lead and think you’re going to get the W.

“Every play, every detail, everything matters in this league, so that’s one thing I took away for sure.”

As was his routine in preseason games, Richardson arrived at Lucas Oil Stadium early “to get my body right, get my mind right. Go through the script of the game, make sure I’m precise on plays, make sure I’m here, just feeling the building, feeling the atmosphere, feeling everything.”

“I was pretty hyped getting here,” Richardson said.

Postgame was a tad more somber.

“I was a little hurt because I felt like we had it,’’ he said. “We’ve just got to clean some things up as an offense. I feel like the defense helped us out a lot. We just couldn’t do anything for them at the time.

“I felt good throughout the game and that’s something we’ve got to learn from.’’

You can follow Mike Chappell on Twitter at @mchappell51.