ST. PETERSBURG -- For Mets right-hander Christian Scott, it seemed larger than a Major League debut. It was more like a premiere, uncommon poise under the bright lights, the promise of some really big things.

The inevitable headlines -- Great Scott! -- might sound like a cliché. But they won’t be wrong. Scott was indeed great against the Rays on Saturday night, even though the Mets' top pitching prospect didn’t figure in the decision at Tropicana Field.

The Mets fell, 3-1, after right-hander Adam Ottavino issued a bases-loaded walk to pinch-hitter Austin Shenton in the eighth inning -- Ottavino’s full-count pitch was low -- and Sean Reid-Foley promptly issued a bases-loaded walk of his own. It ruined the Mets’ prevailing storyline.

But Scott was still the talk of the Mets’ clubhouse.

“It was awesome … as good as advertised,’’ catcher Tomás Nido said.

“It was a pretty impressive outing,’’ manager Carlos Mendoza said. “This is what we saw from him in Triple-A -- the body language, the ability to make pitches when he has to.’’

Scott said he felt prepared.

“A lot of people told me I’d have trouble sleeping [the night before]. … I slept like a baby,’’ Scott said. “I know my stuff is going to play at this level. I have confidence in my work, preparation and routine.’’

Scott went 6 2/3 innings and allowed five hits with six strikeouts and one walk. The first three Rays he faced all notched hits, putting him in early trouble, but then he proceeded to retire 12 straight batters.

Mendoza said the Rays came out aggressive against Scott’s fastball, then Scott made the adjustment and went to his array of breaking pitches, particularly his sweeper and slider.

Getting out of the first inning with just one run allowed, including a strikeout of Randy Arozarena (on a full-count 96.3 mph fastball) and a double-play ball, was Scott’s chosen highlight.

“That kept us in the game early, and I was able to really cruise after that,’’ Scott said.

There was trouble in the fifth inning when Jonny DeLuca reached on a fielder’s choice, then stole second and headed to third on a throwing error by Nido. With two outs and the potential go-ahead run 90 feet away, Scott struck out Jose Siri on a devastating sweeper.

Scott was one pitch away from making it through the seventh inning, but Rays catcher Ben Rortvedt drilled Scott’s 1-2 pitch up the middle for a single. That was Scott’s 94th pitch (67 were strikes), and Mendoza went to the bullpen.

As Scott walked slowly into the dugout, he pulled on the bill of his cap to acknowledge a standing ovation from the thousands of Mets fans stationed on the third-base side.

The Mets let the game get away in the eighth inning. With the bases loaded and one out, shortstop Francisco Lindor delivered an eye-popping play to save a run. He flagged down Arozarena’s high bouncer deep in the hole, then whirled on the run and delivered a perfect throw to force Yandy Díaz at the plate.

“Unbelievable play,’’ Mendoza said. “Knowing the situation, for him not only to get to the ball, but to get rid of it and have a perfect throw to the plate … pretty impressive play.’’

But Ottavino then walked Shenton, forcing in the Rays’ lead run. Even in defeat, though, Scott’s exploits were notable.

Scott, the Mets’ No. 5 overall prospect, was focused and efficient as he pitched in front of dozens of family members and friends from the South Florida town of Coconut Creek, about a four-hour drive from The Trop.

Afterward, Scott said he visited with the entire contingent and presented his first strikeout ball to his parents.

“From start to finish, it was awesome,’’ Scott said.

But not perfect.

“He was great,’’ Ottavino said. “It’s just disappointing we weren’t able to win for him.’’

“Good fastball, really good sweeping breaking ball,’’ Rays manager Kevin Cash said. “Kind of gave us fits. I didn't think we had bad at-bats, I think that kid just had really good stuff, and you'd like to see him stay healthy and have a great career."