SAN DIEGO -- Baseball hasn't always been kind to Dusty Coleman.

Until Monday, the 30-year-old infielder had only five major league at-bats to show for nine seasons in professional ball.

"I've thought about what I should be doing at times," Coleman admitted Thursday night. "But as long as I could put a jersey on and provide for my family, I wanted to play. ... Everyone dreams of hitting a homer in the major leagues."

That dream came true for Coleman on Thursday night at Petco Park.

He hit a three-run homer off New York Mets reliever Tyler Pill in the fifth inning, and it turned out to be a key blow in the Padres' 7-5 win that earned San Diego a split of the four-game series at Petco Park.

It was the first major league homer for Coleman, who was hitting only .209 -- although he had 14 homers -- for Triple-A El Paso when the Padres promoted him Monday. He got the call when regular shortstop Eric Aybar was ruled out for the rest of the season with a fractured bone in his left foot.

Since joining the Padres and sharing time at short with Rule 5 rookie Allen Cordoba, Coleman is 3-for-8 with a double, a home run and four RBIs.

"That was awesome," Coleman said of his blast that carried 417-feet to right center. "I'm not trying to think about the past right now. I want to stay in the moment."

"I love seeing moments like that," said Padres manager Andy Green, who was also a borderline performer as a player. "It's a lifetime dream come true in one moment."

Coleman wasn't the Padres only hero Thursday.

Rookie center fielder Manuel Margot opened the game with a homer and hit a bases-loaded double an inning later. Right-handed starter Luis Perdomo allowed one run through the first six innings before faltering. Right-handed reliever Phil Maton got the final out in the seventh to cut off the Mets' four-run inning, then struck out the side in the eighth.

And left-hander Brad Hand, who became the Padres' closer when Brandon Maurer was traded to the Kansas City Royals on Monday, got his second save in as many nights and his fifth on the season.

"We honestly played a very sloppy, ugly baseball game," Green said. "But we won."

While Coleman has been savoring his return to the major leagues, things didn't work out quite so well for Mets 23-year-old right-hander Chris Flexen, who last only three innings in his major league debut.

The first batter he faced, Margot, homered. Flexen allowed four runs (three earned) on five hits, four walks and a hit batter with two strikeouts.

"I told myself at that moment, 'Hey, welcome to the big leagues," Flexen said of Margot's homer. "It was a tough one to swallow there, a tough outing to swallow. But I'm still living the dream here. It was a dream come true. Obviously, it didn't go how I wanted it to, but it was still fun."

Mets manager Terry Collins said of Flexen, "Well, he's got a good arm. I told him when I took him out, he's gonna pitch a long time in this league. He's just got to command the strike zone a little better."

It is unlikely that Flexen will forget the first inning of his career.

After New York's Michael Conforto doubled to open the game and come around to score on two groundouts, Flexen gave up a homer to the first hitter he faced in the majors, then watched two Padres get thrown out at the plate.

Margot opened the bottom of the first with a 358-foot homer into the left-field-corner seats. It was Margot's fourth game-opening homer of the season, one shy of the franchise's single-season record set by Will Venable in 2011.

Flexen then walked Carlos Asuaje and gave up a single to Wil Myers, and both runners advanced on an infield out.

Then matters got weird.

Cory Spangenberg topped a ball between the mound and the plate. Asuaje tried to score and was initially ruled safe by plate umpire Vic Carapazza. However, Collins challenged the call, and Asuaje was ruled out after an 80-second review.

Myers then tried to score from third on a fake double steal, only to be thrown out at the plate by second baseman Wilmer Flores. This time the Padres challenged the call ... and lost.

Flexen's debut didn't improve in the second.

Jabari Blash singled, Flexen hit Coleman with a pitch, and Luis Torrens walked to load the bases. After Perdomo struck out, Margot drove a two-run double to center with Torrens scoring on an error to make it 4-1. Margot had a career-high three RBIs after two innings.

Coleman then homered in the fifth off Pill, who retired the first two Padres in the inning before issuing back-to-back walks in front of Coleman.

The Mets climbed back into the game with a four-run seventh that was extended when the Padres were unable to convert consecutive double-play opportunities.

With a runner on first and two out, Asdrubal Cabrera singled and Yoenis Cespedes followed with a RBI double. Left-hander Hector Torres replaced Perdomo and balked home Cabrera before giving up a two-run, 368-foot homer to Jay Bruce, who was playing first in place of the traded Lucas Duda.

NOTES: The Mets traded 1B Lucas Duda to Tampa Bay for RHP Drew Smith. RHP Chris Flexen, who was called up from Double-A Binghamton to start Thursday's series finale against the Padres, took Duda's immediate spot on the 25-man roster, although Dominic Smith is expected to be promoted from Triple-A Las Vegas to play first. Drew Smith was optioned to Binghamton. ... The Padres promoted LHP Kyle McGrath from Double-A San Antonio to strengthen their bullpen and optioned RHP Kyle Lloyd back to Triple-A El Paso. ... San Diego INF Yangervis Solarte (oblique) began what is expected to be a short rehab assignment with El Paso on Thursday. ... Padres C Austin Hedges will catch five to seven innings in the rookie-level Arizona League on Friday as a final step before being activated from the concussion disabled list.