SAN DIEGO -- A year ago, the San Francisco Giants were heading toward their second World Series championship in three years.
On Tuesday, they again hit the bottom of the National League West.
Chris Denorfia drove in the winning run with a seventh-inning single, and the San Diego Padres earned a 3-2 victory over the Giants at Petco Park.
The win allowed the Padres (62-76) to drop the Giants (61-77) into sole possession of last place in the division. San Francisco has lost three of its past four games. San Diego can sweep the three-game series with a win Wednesday.
Driving in runs in key situations has been among the Giants' biggest problems.
Leadoff hitter Angel Pagan, who went 3-for-4 with a double and a triple, opened three innings with hits. He never scored despite reaching third base each time. The Giants were 3-for-15 with runners in scoring position, and they left 11 runners on base.
"It's been an issue for a while," Giants manager Bruce Bochy said. "It reared its head again tonight. That's a game we let get away. For some reason, we couldn't get Pagan in. He did a great job in getting in scoring position three times. We just couldn't execute or get him in. We had a tough time getting that big hit."
That wasn't the case for the Padres. Though they were outhit 11-7, the Padres generated enough offense to prevail.
Nick Hundley drew a walk to lead off the seventh, and Ronny Cedeno singled to left off reliever Jake Dunning, allowing Hundley to advance to third. Javier Lopez, who replaced Dunning, retired pinch hitter Mark Kotsay on a weak fly to short, but Denorfia followed with a hit to left, bringing home Hundley for the game-winner with two outs.
Dunning (0-2) gave up a run on one hit and a walk without retiring a batter. He was recalled from Triple-A Fresno before the game.
Tim Stauffer (3-1) struck out three and allowed two hits in 1 2/3 scoreless innings to pick up the victory. Huston Street pitched the ninth for his 27th save, retiring Hector Sanchez with the tying run on second base.
San Diego starter Robbie Erlin worked 5 1/3 innings, allowing two runs on six hits with five strikeouts and two walks. Erlin pitched out of a bases-loaded jam in the first, then set down 11 of the next 13 Giants before giving up back-to-back, sixth-inning singles to Brandon Belt and Buster Posey, who both scored. Pablo Sandoval and Joaquin Arias hit RBI singles.
"He threw well," Padres manager Bud Black said of Erlin. "His tempo in between pitches was good. I like his heartbeat and I like his style. There are some things he is going to improve on, but he pitched well."
Posey left the game after the sixth with a finger injury on his throwing hand.
"He's doing all right. He ripped a nail off his finger," Bochy said. "We'll see how he's doing tomorrow."
Giants starter Madison Bumgarner allowed two runs on five hits with six strikeouts and two walks (one intentional) in six innings. Bumgarner has managed just one win in eight starts since the All-Star break, going 1-4. The Giants have scored only 13 runs in the 57 innings he's pitched in the second half.
Bumgarner retired 12 of the 13 hitters he faced before running into trouble in the fifth. He gave up a one-out double to Kyle Blanks, who scored on Hundley's double to center with two outs.
After an intentional walk to Cedeno, Erlin produced his first major league hit, a bloop single over the head of second baseman Tony Abreu, scoring Hundley to give San Diego a 2-0 lead. Black considered pinch-hitting for Erlin, then decided against it.
NOTES: Padres OF Will Venable agreed to a two-year extension that will pay him $4.25 million annually. ... Padres 3B Chase Headley sat out his sixth consecutive game with a lower back injury. Headley could return for Wednesday's game against the Giants, Black said. ... The Giants recalled INF Ehire Adrianza, Dunning, RHP George Kontos, INF Nick Noonan, OF Francisco Peguero and OF Juan Perez from Triple-A Fresno. The club purchased the contracts of RHP Heath Hembree and C Johnny Monell from Fresno. To make room, the Giants designated INF Kensuke Tanaka and LHP Dan Runzler for assignment. ... San Diego recalled RHP Anthony Bass, RHP Brad Boxberger and RHP Brad Brach from Triple-A Tucson. ... San Francisco LHP Jeremy Affeldt, on the disabled list since July 21 with a left groin strain, pitched to hitters Tuesday, and Bochy was pleased with the reliever's progress. Affeldt will be re-evaluated Wednesday. ... The game drew a crowd of 19,889.