OAKLAND, Calif. (AP) -When Ozzie Guillen learned that alcohol is banned after games in the Coliseum clubhouses these days, the Chicago White Sox manager responded with profanity and anger.

His club couldn't muster nearly that much passion during the actual game - and the Oakland Athletics beat Jon Garland to give another boost to their playoff chase.

Esteban Loaiza outpitched Garland with seven innings of three-hit ball, and the A's opened a key homestand with a 4-2 victory over the White Sox on Friday night.

Marco Scutaro had a career-high four hits and Mark Kotsay hit a run-scoring triple as the first-place A's produced just enough offense to back Loaiza's fourth straight outstanding start at the Coliseum. Oakland also maintained its five-game lead over Los Angeles in the AL West despite going 0-for-16 with runners in scoring position.

Oakland was forced to generate its runs with smarts and resourcefulness, and manager Ken Macha 's team showed plenty of both.

''There is a lot on the line in this series,'' Macha said. ''I'm sure they looked up there and saw Detroit won and Minnesota lost, and we paid attention to the Angels winning. That's what the end of September does.''

The White Sox remained two games behind Minnesota in the wild-card race, but dropped four games behind Detroit in the AL Central chase.

Chicago had plenty of frustration after the game, and not just because its hitters couldn't solve Loaiza. Guillen was stunned by the A's postgame beer ban, which has been in place since midseason following Loaiza's arrest on suspicion of drunk driving.

''He doesn't run my club. I run my club,'' the mercurial manager said of A's general manager Billy Beane while complaining loudly within earshot of reporters.

Garland (17-5) lost for just the second time in 18 starts, yielding nine hits and three runs in 5 2-3 rocky innings - his shortest start since July 29. Guillen touted Garland's candidacy for the AL Cy Young Award before the game, but his ace right-hander, who was 13-1 since June 8, never got comfortable in chilly Oakland.

''I didn't have much, to tell the truth,'' Garland said. ''I did it to myself. I should be able to throw strike one, and wasn't able to do it. I couldn't get my breaking ball over for a strike. (In) 32 starts, you're not going to have it all the time.''

Loaiza (10-8) was outstanding in his first start against the White Sox since leaving the club after the 2004 season. He retired 16 of Chicago's first 17 batters, yielding only Rob Mackowiak 's solo homer in the third, and escaped his only jam in the sixth with just one run allowed.

''That's a great team, but we were playing strong and I felt really good, especially at the end,'' Loaiza said.

Joe Kennedy and Justin Duchscherer struck out the side in the eighth, and Huston Street pitched the ninth for his 33rd save in 41 chances.

Nick Swisher and Mark Ellis hit consecutive sacrifice flies in the fourth inning for the A's, who finish the season with 17 games in 17 days, including this 10-game homestand.

After a slow adjustment to the A's, Loaiza has been the dependable starter Oakland needed during its playoff push, going 5-0 in seven strong appearances before getting pounded at Tampa Bay last Saturday.

Loaiza and fellow starters Joe Blanton and Dan Haren have 10 wins apiece since June 8 - and Barry Zito , who has nine wins in that span, could join them with a victory Saturday. Combined with standout defense, the A's have been able to win without big hits.

''We've really been below-average in hitting,'' said Eric Chavez , who went 0-for-2 but scored the go-ahead run. ''Defense and pitching has been the name of the game for us.''

Loaiza retired Chicago's first seven hitters before Mackowiak's homer. Oakland tied it later in the third inning when Scutaro beat out an infield single and scored on a triple by Kotsay, who returned to the lineup after missing the just-concluded six-game trip with back problems.

The A's put at least one runner in scoring position in each of Garland's last five innings. Garland left with his head down in the sixth after two more Oakland hits.

''Tough decision to make, to take him out,'' Guillen said. ''This kid has a chance to win 20 games, but I had to think about getting the team a win. ... If you don't throw a strike against these guys, you get in trouble. All of a sudden, you're in the fifth inning and you have 100 pitches.''

Notes: A's DH Frank Thomas ' second-inning double against his former team was the 952nd extra-base hit of his career, tying him with Mickey Mantle for 37th place on baseball's career list. ... A's RHP Rich Harden will throw a simulated game Saturday, the latest step in his quest to return to the mound for the first time since early June. ... Kotsay's back spasms had kept him out of 17 of the A's previous 34 games.