The Mets got their closer back Thursday night.

Most importantly, Edwin Diaz looked more like his dominant 2022 version than the reliever who struggled so mightily this season before going on the IL on May 29.

Diaz was activated prior to the series finale between the Mets and Marlins at Citi Field after he was sidelined due to a right shoulder impingement, and worked a perfect ninth inning in his team’s come-from-behind, 3-2 victory.

Diaz threw 15 pitches, 11 of which were strikes.

His fastball popped — it averaged 98.4 mph, up from his season average of 97 mph — and his slider was sharp. It resembled the Diaz pre-torn patellar tendon.

“I feel 100 percent. I saw I was throwing 99, 100 [mph],” Diaz said. “I didn’t do that early in the season. I was locating the pitches the way I wanted to. I was doing my job.”

Diaz said he began feeling shoulder discomfort a few days before going on the IL, and thinks the time off has helped him.

He took a few days to rest, then began working on his mechanics with pitching coach Jeremy Hefner. Watching film, they noticed he was going too much side-to-side before delivering the ball.

“That was the main thing for me,” Diaz said. “If I keep doing that, staying through to home plate, I will be fine.”

Diaz missed all of last season after suffering the aforementioned injury in the World Baseball Classic.

He started this year well, allowing just nine base runners in his first 9 ²/₃ innings despite somewhat diminished velocity. But then struggles came.

He was touched up for eight earned runs, 10 hits and two home runs over the next 4 ¹/₃ innings.

He lost his closer’s job and blew four saves, his ERA rising to 5.40.

The Mets used several different relievers as closer while Diaz was out to little success.

Adam Ottavino and Jake Diekman have both blown save opportunities in the ninth inning.

The Mets have six losses when leading after eight innings this year and have blown 11 saves, which has factored in heavily to their shoddy start at seven games under .500 and a whopping 15 games in the loss column behind the NL East-leading Phillies.

Diaz appeared in two rehab games with High-A Brooklyn and struck out three over two scoreless innings.

Manager Carlos Mendoza didn’t hesitate when asked about Diaz’s role as the team’s closer on Wednesday, and he made the manager look like it was the right choice in his first outing back.

“I liked the sequencing today, the way he mixed his pitches, the fastball-slider,” Mendoza said. “He went slider-slider-fastball-fastball-slider. He didn’t get slider-happy or just fastball-happy. … The key tonight was the sequencing.”