LOS ANGELES - Jake Peavy won his NL-leading 17th game and the NL wild card-leading San Diego Padres backed him with four homers in a 9-4 victory over the Los Angeles Dodgers on Tuesday night.

Brian Giles, Khalil Greene, Kevin Kouzmanoff and Geoff Blum homered for the Padres, who extended their lead over second-place Philadelphia to 2 1/2 games with the Phillies' 8-2 loss to Colorado. San Diego's lead over the third-place Dodgers is 3 1/2 games.

The Dodgers fell to 6-10 against the Padres this season in the opener of a crucial three-game series between the NL West rivals. They host three games against Arizona starting Friday in a week that could decide the Dodgers' playoff fate.

Peavy (17-6) allowed two runs and five hits in seven innings, struck out five and walked two. The right-hander has won each of his five starts against Los Angeles this season, including three at Dodger Stadium.

Pitching on seven days' rest, Esteban Loaiza (1-1) gave up six runs and six hits in 3 1-3 innings, struck out five and walked four. The right-hander stumbled from the start, walking three of the first four batters he faced.

Loaiza gave up back-to-back homers to Greene and Kouzmanoff in the third. Loaiza was booed when pitching coach Rick Honeycutt left him in after visiting the mound during the inning.

San Diego jumped on the Dodgers in the first, taking a 2-0 lead on a bases-loaded sacrifice fly by Greene and an RBI single by Kouzmanoff.

Giles sent a 3-0 pitch from Loaiza into the right field pavilion with two outs in the second, increasing San Diego's lead to 3-0.

The Padres piled on in the third, with the consecutive homers by Greene, his 21st, and Kouzmanoff, his 16th, that made it 6-0.

San Diego added three runs in the seventh. Blum homered off Rudy Seanez, Mike Cameron scored on a wild pitch and Brady Clark added an RBI single to keep the Padres ahead 9-2.

James Loney hit a two-out homer in the third for the Dodgers. Jeff Kent had an RBI single in the sixth and Loney drove in a run with a single in the seventh. Chin-Lung Hu homered in the ninth for his first major league hit.

The Dodgers loaded the bases in the eighth, but a groundball by Andre Ethier deflected off first baseman Adrian Gonzalez' glove, and second baseman Blum hustled after it and threw to pitcher Heath Bell covering first for the third out as Ethier made a headfirst slide.

Notes:@ Peavy improved to 9-1 on the road. ... He hasn't lost to the Dodgers since Sept. 13, 2003. ... The Dodgers had won seven of their previous eight at home. ... Kouzmanoff has hit safely in 15 of his last 18 games, with three homers since Aug. 22.