PITTSBURGH -- Most of the more than 32,000 people who showed up at PNC Park on Friday night stuck it out not only during a rain-delayed start of more than two hours but also while the hometown Pittsburgh Pirates appeared for a time to be headed toward a loss.

It's likely the crowd stayed to hear a postgame concert by the band Chicago, but it worked out from a baseball standpoint.

Gregory Polanco hit his first career pinch-hit homer, a three-run blast that bounced into the Allegheny River, to highlight a six-run seventh inning in the Pirates' 10-6 comeback win over the San Diego Padres.

"Couldn't ask for any more," Pittsburgh manager Clint Hurdle said of the homer. "We were just looking for an opportunity to get us closer. There were two guys out there (on the bases) and a base hit has a chance to score both of them, a good out would score one of them. The swing he put on it scored three of them."

Polanco's 434-foot homer, which cleared the stands in right field off reliever Kirby Yates (2-2), gave the Pirates a 7-6 lead. Adam Frazier's sacrifice fly later in the inning increased the advantage to 8-6, and Josh Harrison added a two-run single.

Yates was charged with six runs on four hits in one-third of an inning.

"He wasn't sharp today," manager Andy Green said of Yates. "He's been sharp all season for us. It was just one of those days for him."

Yates was one of six Padres pitchers.

"Bullpen's been sharp for a while. It wasn't a sharp night for us," Green said.

A.J. Schugel (2-0) pitched one-third of an inning for the win.

The Pirates (53-56) won their second straight game and climbed to within 4 1/2 games of the first-place Chicago Cubs in the National League Central.

San Diego (48-60) lost for the fifth time in the past 11 games.

The game was scoreless through four innings. The Padres came out of the fifth with a 3-2 lead, and Yangervis Solarte's 11th homer increased that to 4-2 in the sixth.

David Freese led off the Pittsburgh sixth with his eighth homer, making it 4-3, and Frazier's RBI single later in the inning tied it 4-4.

Manuel Margot's ninth homer, a solo shot to left off Pirates reliever Joaquin Benoit, broke a tie to give San Diego a 5-4 lead in the Padres seventh. Cory Spangenberg drew a bases-loaded walk later that inning for a 6-4 lead before Pittsburgh's big inning.

"A good win. All I can say," Harrison said. "We never gave up. We got down early, but just kept fighting. Those are the wins you enjoy right there."

Travis Wood, making his first road start in a Padres uniform, pitched into the sixth. He allowed four runs and six hits, with five strikeouts and two walks.

Green said in hindsight he regretted sending Wood back out in the sixth. Wood gave up Freese's homer and a bloop single to Jose Osuna before he got pulled.

"I felt great. I really felt good," Wood said. "It's a shame I couldn't at least get an out there, let alone finish the inning.

"I threw a back-door slider that Freese was able to hit out. And then a jam shot that falls in and (I'm) out of the game."

Pittsburgh starter Ivan Nova went six innings. Only one of his four runs allowed was earned, and he gave up six hits while striking out five and walking two.

"It was really fun to watch the guys battle the whole game, see Polanco come in off the bench and hit a laser," Nova said. "It was fun to watch."

NOTES: San Diego RF Matt Szcur got hit in the right wrist by a pitch in the eighth. He had it heavily wrapped after the game and was expected to have X-rays, manager Andy Green said. ... The start was delayed two hours, five minutes by rain. ... Pittsburgh 2B Josh Harrison (left lower leg) returned after missing three starts, with one pinch-hitting appearance. ... Pittsburgh C Francisco Cervelli (unspecified injury) returned after missing two starts. ... San Diego OF Travis Jankowski was optioned to Triple-A El Paso. ... San Diego RHP Jered Weaver (left hip inflammation) was transferred to the 60-day disabled list.