PHILADELPHIA -- Cesar Hernandez gave Philadelphia a fast start, homering on the first pitch from Jose Urena. But the Phillies couldn't sustain it and missed a chance to move up in the playoff race.

Peter O'Brien homered and drove in three runs as the Miami Marlins blunted Philadelphia's bid to draw closer in the NL East with a 6-4 win Sunday.

The Phillies remained 6 1/2 games behind division-leading Atlanta, which lost to Washington, with two weeks left.

Nick Pivetta (7-13), who has won only one of his last 11 starts, struck out seven in the first three innings. O'Brien's two-run homer in the fourth inning put the Marlins ahead for good at 2-1.

"(Pivetta's) stuff was electric early," Phillies manager Gabe Kapler said. "I think the only hard-hit ball that comes to mind for me was the home run to O'Brien.

"It looked like he was going to roll and he ran into a little bit of a buzzsaw there."

Miami ended a five-game losing streak. Bryan Holaday added a pair of doubles.

Urena (7-12) allowed one run and three hits through a five-inning stint for his third straight win. He left early because of cramping in his pitching hand.

Urena is 4-0 with a 2.16 ERA over his last five starts dating to Aug. 19, when he was pitching under appeal of a six-game suspension he'd incurred for hitting Atlanta rookie Ronald Acuna with a fastball. He later dropped the appeal, and hasn't lost since.

The cramping, Urena said, was caused by throwing too many curveballs with a new grip he's been using.

"I will be fine," he said later. "It's gone away. ... I threw a couple of curveballs. I kept (the hand) open then because if I squeeze it, it probably gets worse."

The Marlins scored three times in the sixth against Luis Garcia for a 6-1 lead.

With runners at the corners and no outs, O'Brien hit a long fly to right field and Odubel Herrera -- more accustomed to playing in center -- had the ball bounce out of his glove before he smacked his head against the fence. The Phillies wound up getting a forceout at second base as a run scored.

Herrera left the game in the seventh.

Down 6-2, Philadelphia scored twice in the ninth, helped by a two-out error by second baseman Starlin Castro. Rhys Hoskins struck out with a runner on to end it.

TRAINER'S ROOM

Marlins: Urena was pulled for precautionary reasons.

Phillies: 3B Maikel Franco missed his fourth straight start because of pain in his right shoulder. He flipped over a rail and into a camera well last Tuesday.

KLENTAK'S VIEW

Before the game, Phillies GM Matt Klentak was asked if he thought several veteran acquisitions he made before and after the July 31 non-waiver trade deadline could have worked against clubhouse chemistry down the Phillies' sad stretch.

"Whatever it is that caused us to go into a team-wide slump in August is not limited to one factor," he said. "It's probably some kind of combination of a lot of things. I will not sit here and tell you the chemistry changed in such a way that that is the reason we struggled. I don't believe that," he said.

UP NEXT

Marlins: Begin a two-game home set against the Washington Nationals on Monday. They will send RHP Trevor Richards (3-9, 4.85) against RHP Erick Fedde (2-3, 5.12) in the series opener.

Phillies: A three-game home series against the Mets starts Monday with RHP Jake Arrieta (10-9, 3.66) facing RHP Zack Wheeler (11-7, 3.23).