ST. PETERSBURG -- For starters, it was not close to the pitching outing needed by the Mets on Friday night.

Left-hander Jose Quintana couldn’t escape the third inning. The damages: 2 2/3 innings, 10 hits and eight earned runs allowed.

Making matters worse, it wasted a great night of production by the Mets’ offense. Following a 10-8 defeat against the Rays at Tropicana Field, Manager Carlos Mendoza was ready to move forward.

“On a day where we needed length out of the starter because of where we’re at, we didn’t get much out of [Quintana],’’ Mendoza said.

And no one felt worse than Quintana (1-3), the veteran who was coming off his most efficient start of the season (eight innings, three hits and one earned run allowed in a 4-2 win against the Cardinals last week).

Friday night’s pitching line looked like a thrashing, but really, it was death by 1,000 paper cuts. It was missed location, bad counts and soft contact that kept finding holes.

“It’s pretty frustrating when you get that kind of support and you can’t take [advantage of it],’’ Quintana said.

In the second inning, the Mets staked Quintana to a 3-0 lead on a majestic three-run homer by third baseman Brett Baty, who cleared Tropicana Field’s B-ring catwalk with a 43-degree launch angle, the highest of any Mets home run this season. Rays right fielder Harold Ramírez lost sight of the ball and waved his arms in surrender, but the ball soared into the right-field bleachers.

But the Rays roared back with three runs to tie it in the bottom half of the frame, then five runs (on five singles and a walk) in the third, when enough became enough and Quintana was lifted.

Had Quintana shown his normal consistency, the story might have been led by Baty, who had his first multihomer game by adding a 421-foot shot to right in the ninth. It could have featured Francisco Lindor, whose two-out, two-run double in the fifth helped rally the Mets. Or maybe Pete Alonso, who followed with an RBI double of his own, cutting the Rays’ advantage to 9-7.

But those offensive exploits merely became footnotes.

Mendoza said he was grateful for the relief work of Dedniel Núñez (2 1/3 innings) and Danny Young (two innings), who assumed the unexpected bullpen workload. With the Mets amid a 27-day stretch with 26 games, starting pitching length is paramount.

Which made Quintana’s off night hurt even more.

“He just wasn’t crisp,’’ Mendoza said. “His breaking ball wasn’t as sharp. He was missing his spots. The balls found holes, a lot of singles.

“He has been giving us five, six innings. He has always kept us in the game. Today, it got out of hand and he didn’t have it. But overall, he has been that guy who’s going to keep us in games. Today, it wasn’t the case.’’

Mendoza was encouraged by Baty’s offensive showcase.

“Wow, I mean, the power, right?’’ Mendoza said. “The way he drove those two balls was pretty impressive. We know he’s capable of doing that and he has been having good at-bats. You know, he’s always in the fight.’’

But the early-inning knockout of Quintana made things more difficult.

“I think [the Rays] had a good plan, and I needed to change my approach,’’ Quintana said. “They found the holes. They attacked. It was crazy because it all happened so quickly.

“I felt great [physically]. I just need to get more sharp. I’m going to keep competing. I just have to turn the page and get focused. When you get that support and [eight] runs, it’s very frustrating to not take advantage of that.’’