Matt Harvey returned to the scene of the crime on Wednesday. And no, it wasn’t a nightclub or a golf course.

It was Chase Field, where the Mets pitcher made his major league debut on July 26, 2012. The right-hander allowed just three hits over 5 1/3 scoreless innings in that game and struck out 11 batters – still a record for a Mets pitcher in his debut performance.

Reeling from three straight rough outings and a team-imposed, three-game suspension for missing a game after spending all night partying and the next day playing golf, Harvey needed a Chase Field pick-me-up in the worst of ways.

Though he pitched better than he has in nearly a month, he didn’t get it.

After allowing three runs over 5 2/3 innings and exiting the game with a 4-3 lead, it felt more like a hangover. Yasmany Tomas tied the game with a run-scoring double in the seventh and the Diamondbacks won it in extra innings 5-4 on a Chris Herrmann’s first career walk-off homer in the 11^th.

For Harvey, at least, it was a step in the right direction.

“Obviously, if I could go back and change a couple pitches, I would,” Harvey said, “but overall, I felt much better today and probably the best I’ve felt in two years. So I definitely take a lot of things I did today as a positive, but there was definitely a few pitches I wish I could have back.”

Yeah, like the 2-0 pitch he threw to Jake Lamb in the third inning. But wait, let’s first set the stage for you.

According to the New York tabloids, Harvey’s regrettable night out on the town may have been caused by seeing tweets of his supermodel girlfriend Adriana Lima hanging out with her ex-boyfriend, New England Patriots wide receiver Julian Edelman, at a Met Gala after-party.

And wouldn’t you know it, someone in the crowd behind home plate yelled out “Adriana!” just as Harvey threw his 2-0 pitch to Lamb. With Chris Owings at first, Lamb drilled the pitch into the left field stands for a home run.

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It was Herrmann’s homer off Rafael Montero that stung the most, but things couldn’t get much worse for the Mets, who have lost a season-high seven straight games, have five key players on the disabled list and can’t be sure what they’re getting any longer from The Dark Knight, Harvey’s nickname.

Lately, Harvey has been more like The Riddler.

Once one of the best pitchers in the game, he clearly hasn’t been the pitcher he once was. Of course, he’s also had to undergo Tommy John surgery and thoracic outlet syndrome surgery. But his stuff doesn’t bite the way it used to. His slider isn’t quite so sharp, he’s barely throwing his curveball at all, and his velocity is down on his fastball, which is getting whacked.

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On Wednesday, exactly one week after apologizing to his teammates for bailing on them in a game he wasn’t scheduled to pitch, Harvey revealed he’s spent the past handful of days changing a flaw in his mechanics. Upon watching video with pitching coach Dan Warthen, it was discovered he had been throwing from a higher arm slot.

It was a bad habit from last season he somehow picked up accidentally. Why he didn’t realize that is puzzling, however, considering he told reporters after Wednesday’s game that he would get a tingling sensation in his right index finger by throwing from that angle and as a result, his pitches weren’t moving the way they should.

“We worked really hard this last week on throwing from my normal arm slot, watching as lot of video from 2013 and most of ’15, and we took some video from my bullpen this past week, and things are starting to feel much better,” Harvey said. “I’ve got to keep working on that, but I think I’m close to where I want to be.”

As a team, the Mets are a completely different story. Like Mets manager Terry Collins said, “When things aren’t going good, nothing goes good.” But Collins was adamant during his postgame news conference that he wouldn’t let the clubhouse implode.

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“It’s very easy to unravel right now and I will not let that happen here. We are not going to do that,” he said. “We’re going to stay together, play together, get on the same end of the rope and pull together, and I will not let this team get down. I will not do that.

“We got back to .500 and we’ll do it again. We’ve got to get healthy a little bit … but we’re going to turn this around.”

A big part of the Mets’ recovery depends on Harvey – and Collins said he saw “bright things” from his pitcher against the Diamondbacks. Harvey, he said, maintained his velocity, did a much better job locating his pitches and overall, he “made a step forward” on Wednesday.

“This is a process that may take a couple of times,” Collins said, “but he felt good about it and that means a lot. His confidence speaks volumes here.”

Reach McManaman at [email protected]. Follow him on Twitter @azbobbymac and listen to him live every Wednesday night between 7-9 on Fox Sports 910-AM on The Freaks with Kenny and Crash.

Coming up

Friday: At San Diego, 7:10 p.m., Diamondbacks RHP Taijuan Walker (3-3, 3.91) vs. Padres RHP Jered Weaver (0-4, 6.05).

Saturday: At San Diego, 7:10 p.m., Diamondbacks LHP Robbie Ray (2-3, 4.57) vs. Padres RHP Luis Perdomo (0-0, 4.19).

Sunday: At San Diego, 1:40 p.m., Diamondbacks RHP Zack Godley (1-0, 1.93) vs. Padres LHP Clayton Richard (2-5, 4.86).