SAN DIEGO — Chris Denorfia hit a go-ahead RBI single in the seventh inning to lift the San Diego Padres to a 3-2 victory over the San Francisco Giants on Tuesday night.
Nick Hundley drew a leadoff walk in the seventh from rookie reliever Jake Dunning, who was called up earlier in the day from Triple-A Fresno. Ronnie Cedeno followed with a single to send Hundley to third and bring on reliever Javier Lopez.
Denorfia lined a 1-2 pitch to left for the single that broke a 2-all tie.
Dunning (0-2), who made his major league debut in June, took the loss. Tim Stauffer (3-1) got the win with 1 2-3 innings of shutout ball.
Huston Street pitched the ninth for his 26th save in 27 chances.
Defending World Series champion San Francisco (61-77) dropped into last place in the NL West, one game behind San Diego.
San Francisco catcher Buster Posey was pinch hit for in the seventh after he appeared to hurt his right hand on a wild pitch thrown by Madison Bumgarner in the sixth inning.
Posey shook his right hand after Bumgarner's pitch in the dirt and spent a couple of minutes being attended to by a trainer before he stayed in the game and completed the inning.
Giants center fielder Angel Pagan had a single, double and triple heading into his final at-bat in the ninth when he struck out.
San Diego took a 2-0 lead in the fifth following a leadoff double by Kyle Blanks and Hundley's one-out double. After Cedeno was walked intentionally, rookie pitcher Robbie Erlin drove in the second run with a bloop single. It was Erlin's first major league hit and RBI.
The Giants tied it in the sixth. After consecutive singles by Brandon Belt and Posey to start the inning, Pedro Sandoval and Joaquin Arias followed with consecutive RBI singles with one out.
San Francisco stranded 10 runners one night after leaving nine on base in a 4-1 loss to the Padres.
Bumgarner lasted six innings and gave up two runs and five hits with six strikeouts and two walks.
Since the All-Star break, Bumgarner has just one winning decision in nine starts. The left-hander is 1-4 with a 2.67 ERA in that span.
Erlin allowed two runs and six hits in 5 1-3 innings. The left-hander struck out five and walked two.
NOTES: San Francisco RHP Heath Hembree made his major league debut with one inning of perfect relief . Padres rookie RHP Burch Smith will start on Friday against Colorado. Smith, who was recalled from Triple-A Tucson on Monday, is 0-1 with an 18.41 ERA in three starts earlier this season with San Diego . Giants RHP Tim Lincecum (8-13, 4.38 ERA) opposes Padres LHP Eric Stults (8-12, 3.81) in the series finale Wednesday.