Randy Wolf pitched a three-hitter for his first complete game of the season and the Milwaukee Brewers kept the San Francisco Giants from extending their lead in the NL West with a 3-0 victory Friday night.

The Giants remained a half-game ahead of second-place San Diego, which lost 14-4 at St. Louis. San Francisco is still in sole possession of first place in the division in September for the first time since 2003, the club's last year in the playoffs.

Prince Fielder hit an RBI single in the first, Carlos Gomez drove in a run on a groundout in the fifth and Milwaukee scored another on reliever Jeremy Affeldt's wild throw home for a costly error in the seventh.

Wolf (12-11) tossed his 13th career complete game and ninth shutout. It was his first in both categories since a 4-0 win on Sept. 3, 2008, against the Cubs at Wrigley Field while with the Astros.

A night after the Giants hit three home runs in a 10-2 rout of the rival Los Angeles Dodgers, they couldn't do much of anything against Wolf — getting just three singles. San Francisco's poor defense didn't help matters by committing two errors.

"We owe it to everybody who's chasing this team that we're going to go out and put our best foot forward," Brewers manager Ken Macha said before the game.

Wolf struck out six and walked two to win for only the second time in his last five starts. The efficient left-hander needed only 57 pitches to get through six innings and finished his 111-pitch gem in 2 hours, 29 minutes. He threw 72 strikes.

Ryan Braun doubled twice among his three hits and scored two runs for the Brewers, who lost two of three at Houston to start their second-to-last road trip of 2010. Milwaukee also dropped the series before that to the Cubs.

Giants rookie Madison Bumgarner (5-6) allowed nine hits to match his season high, struck out five and walked one in 5 2-3 innings. The 21-year-old lefty is still looking for his first win of the season at home, where he's 0-3. Bumgarner has a five-start winless stretch with two straight losses following three consecutive no-decisions since beating St. Louis on Aug. 20.

San Francisco's Edgar Renteria batted leadoff for the second straight game after getting four hits in Thursday night's lopsided win but went 0 for 4.

The Giants dropped the series opener after sweeping a four-game series in Milwaukee in July, outscoring the Brewers 36-7.

Notes: Struggling Giants slugger Pablo Sandoval was on the bench for the second straight night against a lefty starter. The "Kung Fu Panda," as he's known, is mired in an 0-for-15 funk and is 3 for his last 37. Manager Bruce Bochy wasn't sure whether he would play Saturday. ... Macha has his rotation set up that he can send his best pitchers out the final weekend at first-place Cincinnati if the division has yet to be decided. ... The rookie-level Helena Brewers won the Pioneer League title Thursday night. ... Milwaukee RHP Mark Rogers, recalled last Friday from Double-A Huntsville, is set to pitch the second game of a four-game set against Florida next week and also get another start against the Mets. ... Giants draft pick RHP Brett Bochy, Bochy's son, is set to begin throwing early next week as he recovers from reconstructive Tommy John elbow surgery.