SAN DIEGO -- The Miami Marlins were on the ropes.

Trailing by three runs in the bottom of the fifth, the San Diego Padres had two on and their hottest hitter, Wil Myers, at the plate. In the distant background behind Marlins starter Tom Koehler, Miami had a fresh arm getting ready in the bullpen.

And that was where the rubber match of the three-game series at Petco Park turned on Sunday.

Koehler got Myers to bounce into an inning-ending, 5-4-3 double play. Then, before the Padres could retire a batter in the top of the sixth, the Marlins scored six runs on their way to a 7-3 victory.

"That double play, those are the kind of things during the course of the game that turns things around," Marlins manager Don Mattingly said before Miami headed east to continue (by miles) one of the longer baseball road trips possible.

The Sunday win left the Marlins 3-3 after two stops on a Seattle-to-San Diego-to-Philadelphia journey. By the time it is over, the team will have flown close to 7,200 miles.

"Hopefully, we can carry this momentum into Philadelphia," Koehler said. "That was a big team win. Any time you lose the first game and come back to win the series, especially like it played out today, it's huge."

Justin Bour capped the Marlins' six-run sixth inning with a three-run homer. He was the sixth consecutive Miami hitter to reach base.

Until the sixth, Padres starter Luis Perdomo, who was activated from the 10-day disabled list Sunday morning to face the Marlins, was cruising. Through the end of the fifth, Perdomo had retired seven straight batters and nine of 10.

Martin Prado, who started the double play in the bottom of the fifth after stopping the Padres on Saturday night with defensive gems on back-to-back plays in the bottom of the 10th, singled to open the sixth Sunday.

Christian Yelich drew a walk ahead of a RBI single by Giancarlo Stanton. Right-hander Craig Stammen replaced Perdomo and immediately gave up a run-scoring double to Marcell Ozuna. J.T. Realmuto tied the game, driving home Stanton with a single.

That brought up the left-handed-hitting Bour, who pulled a 2-1 slider from Stammen 399 feet into the right field stands.

"It was really the way we started the inning," Bour said. "Their starter was doing a heck of a job. He was cruising there. Then guys got on base to get the line moving. I was thinking the same thing. Fortunately, I put a good swing on it."

Padres manager Andy Green said, "That was tough. Perdomo was throwing really good. I thought he was a little too amped early, his velocity was up and his sinker wasn't as sharp, but he started to hit his stride in the fifth."

Stammen (0-1), who gave up hits to the only three hitters he faced concluding with Bour's homer, was charged with the loss.

Koehler (1-1), who appeared to be close to coming out of the game in the bottom of the fifth inning, allowed three runs on six hits over six innings to pick up the win.

The Padres scored a run in the first and added two more in the fourth when rookie Hunter Renfroe followed a leadoff walk to Yangervis Solarte with his fourth homer -- a 410-foot shot to straightaway center.

San Diego's first run came when Manuel Margot, the team's other rookie outfielder, opened the game with a single, advanced to second on a groundout to the right side and scored on Solarte's two-out single. Margot is now 9-for-16 with a walk in the 17 times he has opened a game as the Padres' leadoff hitter.

NOTES: Padres manager Andy Green was ejected between the seventh and eighth innings after a heated argument with plate umpire and crew chief Paul Emmel. It was Green's first ejection of the season and his third as San Diego's manager. ... To make room on the 25-man roster for RHP Luis Perdomo, the Padres optioned RHP Zach Lee to Triple-A. The Padres want Lee to join the El Paso rotation. Lee went 1-0 with a 5.63 ERA in three games (one start) with San Diego.