CHICAGO -- Barry Zito dominated the best team in baseball -- again.
"The story tonight was Barry. That's two in a row against the White Sox. He went out and (allowed) two hits. He was just outstanding with everything," Athletics manager Ken Macha said.
After signing a three-year contract extension with the Athletics before the game, Kotsay hit a three-run homer in the seventh.
With Oakland leading 2-1, Nick Swisher led off the seventh by reaching on third baseman Pablo Ozuna's second error of the game. Two outs later, Jason Kendall singled up the middle. Then Kotsay followed with his seventh homer of the season off White Sox starter Mark Buehrle, giving the Athletics a 5-1 lead.
"If he buries that changeup down and in against me they're out of that jam and in the game at 2-1. He just didn't locate it," Kotsay said.
Eric Chavez added a two-run homer in the ninth for the Athletics, who have won 12 of 15 and improved to 6-2 against the majors' winningest team.
The game featured a matchup of two of the best left-handers in the league and Zito outpitched Buehrle (10-3) for the second time this week.
Despite being pushed back a day after complaining of pain in his rib cage after throwing a season-high 124 pitches Sunday, Zito (6-8) looked strong. His curveball was effective and he didn't give up his second hit of the game until a leadoff single to Scott Podsednik in the sixth inning. Zito allowed a double to Tadahito Iguchi in the first inning.
"It was similar to last game. We had a two run lead and then we opened it up late. I think earlier in the year getting no run support helped me pitch in close ball games," Zito said.
Zito allowed just one run and improved to 7-2 against the White Sox in his career. He struck out six and walked three. He fooled the White Sox with his curveball and changeup.
"He's an outstanding pitcher. His last four or five starts he's pitching like the old Barry Zito," Buehrle said. "It's not like we're going out there facing some 'Joe Blow' that can't get guys out. He's a Cy Young winner, he's getting back to form and he is going to be tough in the second half."
Buehrle had his nine-game winning streak snapped last Sunday in a 7-2 loss at Oakland after giving up seven runs and a career-high 14 hits over 6 1/3 innings.
His struggles continued against the Athletics on Saturday. Buehrle allowed five runs -- two earned -- on six hits in seven innings. He struck out three and walked two. Buehrle is 2-8 against the Athletics in his career and two of his three losses this season have came against Oakland.
Iguchi followed Podsednik with a walk in the sixth and they moved up on a double steal. Frank Thomas drove in Podsednik on a sacrifice fly. Zito held Iguchi at third by getting Paul Konerko to pop out and he struck out Aaron Rowand on a high fastball ending the inning.
"I was a little disappointed with the way we played today. I think as a team, it was a really weak effort. We're better than this. I saw that everyone (looked) flat in the dugout and in the field," said White Sox manager Ozzie Guillen, who was also upset that starting shortstop Juan Uribe didn't run out a flyball in the seventh.
Bobby Kielty and Eric Byrnes hit back-to-back doubles off Buehrle in the second inning. Kielty scored on Byrnes' double. Then, Ozuna couldn't handle Keith Ginter's grounder at third and Byrnes scored from third giving the Athletics a 2-0 lead.
Oakland padded their lead in the eighth when White Sox reliever Bobby Jenks walked Scott Hatteberg with the bases loaded to score Kielty. Ellis had an RBI fielder's choice and Kendall had a run-scoring grounder to make it 8-1.
Buehrle retired 11 in a row before giving up a leadoff single to Kotsay in the sixth inning.
Kotsay's deal supercedes the final year of his current contract, a five-year deal through the 2006 season. He was 2-for-5 with three RBI. ... The White Sox had their seventh sellout of the season. ... Kendall was 3-for-5 for Oakland. ... Ozuna started at third for Joe Crede. Crede is day-to-day with a sore back.