The official Home Run Derby at Marlins Park occurred three years ago before the All-Star Game, but the unofficial version, featuring two prominent Mets, was underway Monday night.

Robinson Cano and Pete Alonso turned Miami’s empty Fish Tank — just like always — into a launching pad, jump-starting a Mets lineup that spent the weekend searching for a jolt.

With Cano and Alonso each blasting two homers, the Mets rolled to an 11-4 victory that snapped their three-game losing streak.

Cano, who is hitting .412, continued his sizzling play, but the better sign for the Mets (10-14) was the breakout from Alonso, who entered the night still searching for his swing during a disappointing stretch to begin the season.

“It’s a learning process and this kid is maturing by the day at the plate,” manager Luis Rojas said, referring to Alonso, who set an MLB rookie record with 53 homers last season. “He’s always a hard worker, an over-worker, and we have to monitor that and control that, but we are doing some things with him, we are having different conversations, things that he can digest well and put it in the game.”

The Mets received a strong bullpen effort from Chasen Shreve, Jeurys Familia, Brad Brach and Franklyn Kilome after Robert Gsellman labored early and was removed after recording only five outs. The lefty Shreve, in particular, was effective with five strikeouts over 2 ¹/₃ scoreless innings. The rookie Kilome pitched the final three innings and allowed two runs to earn his first major league save.

Gsellman, who moved last week from the bullpen to the rotation, had a second straight abbreviated start, lasting only 1 ²/₃ innings in which he allowed one run on three hits, two walks and a hit batsman. The right-hander was removed after throwing 47 pitches. In his initial start of the season, against the Nationals last Wednesday, he was removed after throwing 33 pitches in two innings.

Dominic Smith’s two-run double in the second got the party started for the Mets, who had loaded the bases with nobody out against Jordan Yamamoto. Michael Conforto and Alonso walked in the inning — with Cano’s single sandwiched in between — before Smith continued his torrid play with a shot to right that extended his team lead in RBIs to 18.

Cano’s first homer of the game, a line drive that just cleared the right-center fence, gave the Mets a 5-1 lead after J.D. Davis was drilled by a pitch to begin the inning. Alonso’s ensuing homer extended that lead.

Alonso, who entered batting .214 with three homers, was on the bench Sunday for a mental break as the Mets lost to complete a three-game Phillies sweep.

“I see [Alonso] work so hard in the cage,” Cano said. “It was great to see him come out tonight and hit two homers because I know as a hitter, especially with what he did in his first year, he’s never been through a situation like this. I can’t wait to see him be the same guy he was last year.”

The Mets turned it into a runaway in the sixth when Cano and Alonso again hit consecutive homers. Cano finished with four RBIs in his first start at second base since returning from the injured list on Friday. He had started the previous three games as the DH. The multi-homer game was Cano’s second with the Mets — last year he blasted three homers in a game against the Padres.

“That’s why I was brought here from Seattle,” Cano said. “Last year was kind of frustrating because once you get hot you get injured or get hit by a pitch. For me there is a lot left in the tank because I always work hard and I am the kind of guy that no matter the situation I am never going to put my head down.”

In the three games against the Phillies the Mets scored nine runs and continued their season-long habit of struggling with runners in scoring position. The Mets were 4-for-13 (.307) with runners in scoring position Monday.