PITTSBURGH -- Mixed alliances weren't an issue for David Phelps Saturday. Sure, his wife and dozens of family and friends were at sold-out PNC Park to watch him pitch in the city of his offseason home.

But Phelps was all about the Miami Marlins, and they were all about him after his nearly spotless six-inning performance in a 3-1 win over the Pittsburgh Pirates.

"I think about where I've been in my career and the sacrifices my family's made for me," said Phelps, who met his wife, a Pittsburgh native, when they were at Notre Dame.

"My wife's family has been so supportive. My brother and his family were up there (in the stands) with my wife and our oldest. That's what it's about. Coming to Pittsburgh where they're all Pirates fans, they can put on Marlins stuff for one night and cheer me on, it's awesome."

Phelps (7-6) pitched six shutout innings, limiting the Pirates to two hits, striking out nine and walking two as he faced just two batters over the minimum. After giving up a single to the game's first hitter, Josh Harrison -- who was erased by a double play -- Phelps set down 13 batters in a row. He struck out five of six at one point, including striking out the side in the third.

"I'm just happy with being able to pitch deeper into the game," Phelps said. "I got on a pretty good roll out of the windup. We were able to get guys out quick and give our guys a chance to score some runs before they got on the board."

Phelps was making his fourth start after spending most of the season in the bullpen.

"Anything we've asked him to do, he's been able to do," Marlins manager Don Mattingly said. "To give us six there, and obviously the zeroes -- he's been great."

Fernando Rodney pitched a 1-2-3 ninth for his 23rd save.

The Marlins, who clinched a weekend series win, moved a half-game ahead of the Pirates and are 1 1/2 games behind St. Louis, which holds the second National League wild-card spot but lost to Philadelphia.

Pittsburgh, which was held to four hits, has lost two in a row after a four-game winning streak.

Chad Kuhl (3-1) was making his seventh major league start, and Pittsburgh had not lost with him on the mound. He picked up his first career loss, pitching six innings, giving up two earned runs (three total) on six hits, with no walks or strikeouts. One of those hits was Xavier Scruggs' first career homer, a two-run shot in the fourth.

"I thought he pitched a very competitive ballgame," Pittsburgh manager Clint Hurdle said of Kuhl. "His first-pitch strikes were good. No walks again. Ten guys retired on three pitches or less. One pitch he'd like to have back. He tried a two-seam fastball to Scruggs, it just stayed on path, straight. The kid put a good swing on it."

Miami took a 1-0 lead with an unearned run in the third. After Miguel Rojas singled to left, Phelps reached on what originally was a putout from right fielder Gregory Polanco to first, but a review ruled Phelps safe. Dee Gordon followed with fly to center that Andrew McCutchen bobbled for an error, allowing Rojas to score.

Martin Prado reached on a fielder's choice, moving Phelps to third, but Kuhl got Christian Yelich to ground into a double play.

The Marlins upped their lead to 3-0 in the fourth. With two out, Ichiro Suzuki doubled to the right-field corner, and Scruggs followed with a shot into the left-field bleachers.

"I guess the biggest thing was, this feels so much better than the minor leagues," Phelps -- who had the ball in his locker stall -- said with a laugh. "Just getting that first one, you can kind of breathe a little bit.

"But that's the thing that was most important, was just being able to provide something for this team. You can get a hit at any time, but the big hits are the ones that really matter."

Kuhl's pitch wasn't elevated, but he wasn't happy with it.

"It was down, but it caught the plate, so I think that it was just one of those ones that didn't have a lot of movement to it down in the zone and he's a good low-ball hitter," Kuhl said.

Pittsburgh foiled Miami's shutout bid in the eighth when Jordy Mercer doubled off the wall in right with one out and, an out later, scored on Harrison's base hit to center to make it 3-1.

NOTES: Pittsburgh placed 3B Jung Ho Kang on the 15-day DL because of a left shoulder injury he got Friday sliding head-first into third in the eighth. He is expected to miss two to four weeks. . ... The Pirates recalled 1B/OF Josh Bell from Triple-A Indianapolis. ... OF Robert Andino, who drove in the winning run Friday, was out of the Miami lineup Saturday as RF Ichiro Suzuki slotted back in after a day off from starting. ... Pirates RHP Tyler Glasnow (right shoulder discomfort) came through a Friday side session fine, manager Clint Hurdle said. The next step is a rehab start, but the where and when remain undetermined. ... Pittsburgh C Chris Stewart (left knee discomfort) was 1 for 8 with four walks and an RBI in his first four rehab games with Double-A Altoona. ... RHP Mitch Keller on Friday allowed two hits in seven scoreless innings for Single-A West Virginia, extending his scoreless streak to 18 innings. ... LF Starling Marte threw out Miami C J.T. Realmuto at the plate Friday for his 15th outfield assist. He led the NL with 16 last season, making him the first Pittsburgh OF with 30 or more assists over two seasons since Dave Parker in 1977-78.