PITTSBURGH -- Jedd Gyorko blasted a 3-run homer among his three hits and the San Diego Padres topped the Pittsburgh Pirates 5-2 on Tuesday night.
Ronny Cedeno added three hits for San Diego, which beat the Pirates for the second straight night to put a dent in Pittsburgh's pursuit of its first NL Central title. St. Louis and Pittsburgh entered the day tied for first in the division.
Luke Gregerson worked the ninth for his fourth save.
Eric Stults (9-13) allowed two runs over five innings to pick up his first win in more than two months. Stults struck out five and walked one.
Andrew McCutchen went 2 for 3 and Marlon Byrd drove in both of Pittsburgh's runs, but the Pirates continued to have problems with the Padres.
Jeff Locke (10-6) struggled with his command, allowing four runs and seven hits in five innings, striking out five and walking three as his second-half struggles reappeared.
A night after getting one-hit by San Diego's Andrew Cashner and his series of 97 mph fastballs, the Pirates were handcuffed by Stults' slower pitches.
The left-hander hadn't won in his previous 10 starts and came in with a 3-9 mark on the road.
Then again, there's no place quite like PNC Park for the Padres. San Diego improved to 30-10 in Pittsburgh since the ballpark opened in 2001.
Stults used his series of slow, slower and slowest offspeed pitches to keep the Pirates off balance.
At one point he retired Pedro Alvarez on a 66-mph changeup and dropped it down to 64 mph to get Josh Harrison to ground meekly to third.
It was enough to prevent one of the National League's top-hitting teams against left-handers from cashing in as the Pirates try to keep pace with St. Louis and Cincinnati in a crowded playoff race.
Locke briefly regained his All-Star form in his last start, when he handcuffed the Chicago Cubs for seven innings to pick up his first win in nearly two months.
The good vibes disappeared in the third, when Gyorko took an 89-mph fastball over the middle of the plate and sent it into the bleachers in left field for his 19th homer of the season.
The Pirates drew within one in the bottom of the inning thanks to a little help from San Diego right fielder Kyle Blanks, who stumbled trying to track down a sinking line drive by Byrd, allowing two runs to score.
Byrd tried to tie the game one batter later when Gaby Sanchez's infield chopper was mishandled by Gyorko at second base.
The ball trickled behind Gyorko but Cedeno -- who spent three mostly forgettable seasons in Pittsburgh from 2009-2011 -- picked it up and fired home to throw out Byrd as he attempted to score from second.
Pittsburgh didn't get closer. Cedeno singled leading off the fifth and came around to score and Pittsburgh's offense disappeared against a trio of San Diego relievers.
The Pirates managed just two base runners over the final four innings, with Cedeno providing a highlight play from deep shortstop against Byrd in the eighth to provide an exclamation point as Pittsburgh stumbled again.
NOTES: Pittsburgh outfielder Starling Marte went 1 for 3 in his first start since suffering a contusion to his right index finger on Aug. 18 ... Pittsburgh C Russell Martin caught his major league-leading 29th base stealer in the ninth when he threw out Will Venable at second ... Padres LHP Cory Luebke will be examined by orthopedic surgeon Dr. Tim Kremchek in Cincinnati later this week. Luebke has been shut down for the season as he attempts to come back from Tommy John surgery in May 2012 ... The series continues on Wednesday when Pittsburgh's Charlie Morton (7-4, 3.54 ERA) faces San Diego's Tyson Ross (3-8, 3.29 ERA).