SAN DIEGO -- Adversity comes in many forms. For a Mets team that had lost four straight games entering Tuesday night, it was not particularly difficult to find in the visiting dugout at Petco Park -- nor in the clubhouse, nor in the coaches’ room, nor anywhere else.

Adversity seemed to surround everyone -- from Pete Alonso, who came away from his Monday showdown with Chris Paddack frustrated and upset, to Brandon Nimmo, who was riding a career-worst slump, to others up and down the Mets’ bench. Given how badly the team had struggled, Alonso called the Mets’ 7-6 victory over the Padres “a must-win.”

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Is this really only early May? The Mets are fighting and acting like it’s September, as evidenced by three of the most vibrant snapshots from Tuesday’s game.

1. Alonso’s revenge
Barely 24 hours before his ninth-inning at-bat, Alonso stood in the Petco Park visiting clubhouse frustrated and embarrassed, talking about his feud with Paddack. The Padres’ pitcher had called out Alonso before Monday’s game, questioning his National League Rookie of the Month Award. He then not only struck out Alonso twice, but pumped his fist and yelped on the mound, inciting grumbles from inside the Mets’ clubhouse. Afterward, Alonso mostly bemoaned his inability to make Paddack pay for his words. He hated even more that he couldn’t help the Mets find their way out of a losing spiral.

It was with all that as a backdrop that Alonso stepped to the plate in the ninth inning of a tie game. When Adam Warren threw him a 2-2 fastball on the inside corner, Alonso demolished it. The ball struck near the third deck of the Western Metal Supply Co. Building in left field, ricocheting down into the abutting bleachers.

“That,” Alonso said, “was awesome.”

Off the bat, the ball traveled 114.7 mph, destined for a spot 449 feet from home. It carried with it most of Alonso’s frustration from the previous night.

“I blacked out for a little bit,” Alonso said. “I just remember touching home. I don’t even remember running the bases.”

When he jogged back on the field for the bottom of the ninth, Alonso crossed paths with Padres star Manny Machado, who winked at him and said simply: “Is that all you got?”

“I said it from the first day -- he’s a guy with a bright future ahead,” Mets teammate Robinson Cano said. “He’s so strong. And what I love about him, he works hard. … After what he did last night, I told him you never remember what happened last night. Just go out there and play your game. You know what? He went out and did really good.”

2. Nimmo’s slump-buster
After a few hitless games, Nimmo said, he tends to become quite conscious of growing slumps. So by Tuesday, Nimmo was acutely aware that he was 0-for-26, struggling to hit balls with authority. He began taking pride in small victories -- grinding out a walk or hitting a line drive right at someone.

Still, as the slump deepened, so did Nimmo’s mood. Long since dropped from leadoff to seventh in the Mets’ batting order, Nimmo grounded out in the first inning and struck out in the sixth to bloat his slump to 0-for-28. Only nine Mets in history have suffered longer streaks, with Rey Ordonez’s 37 straight hitless at-bats in 1997 the record for position players.

That sort of dubious history was weighing on Nimmo as he stepped to the plate in the seventh inning with two men on base and two outs. When Craig Stammen threw him a 92-mph sinker on the outside corner, Nimmo jumped at it, lacing it to left-center field for a game-tying single. Had anyone but Wilson Ramos been the trail runner, the hit likely would have plated two.

“To be able to help the team out today and come through in that situation made me ecstatic,” Nimmo said. “I was really happy about that.”

3. Diaz hits his spot
After Alonso’s homer, the Mets felt secure handing a two-run lead to well-rested closer Edwin Díaz, who had not pitched since Saturday. That feeling lasted only until Diaz walked a batter and allowed consecutive hits to put the tying run on third base with one out. An intentional walk of Machado brought up Eric Hosmer with the bases loaded.

Well aware of Hosmer’s power, Diaz focused as best he could on hitting the corners of the zone, trying either to strike him out or induce a double play. But Hosmer was patient, laying off three close pitches and fouling away another to run the count full.

That preceded Diaz’s masterstroke: a 97-mph fastball that nicked the inside corner, prompting Hosmer to snap his head backward and question home-plate umpire Bill Miller. The pitch, Miller confirmed to him, was a strike. It was also the exact momentum spike that Diaz needed; moments later, he induced a ground ball from Hunter Renfroe to end the game.

“Once I loaded the bases to get Hosmer in there, my goal was just to give him the most uncomfortable pitches I possibly could,” Diaz said. “At 2-2, I thought I struck him out there. But I made a better-quality pitch at 3-2 and was able to get him out of there.”