Baseball's Frank Thomas celebrated the return to his former home field in Chicago Monday with two home runs, but his new team, the Oakland Athletics, lost to the major-league world champions.

The White Sox beat the A's, 5-4, on a bunt single in the 10th inning by Pablo Ozuna.

Despite the win, Chicago still has only the second-best record in the American League this year, with the season about one-quarter complete. The Detroit Tigers have the best winning percentage in the majors (30-14 - .682); they kept their one-game lead over the White Sox in the A.L. Central by shutting out the Kansas City Royals, 8-0.

Boston, Seattle and Toronto were the other A.L. winners. In the National League, Florida, Arizona, Atlanta, Los Angeles, San Francisco and Houston came out on top in their contests Monday.

The Florida Marlins beat the Chicago Cubs in Miami, 9-1, snapping a seven-game losing streak. The Diamondbacks, playing at home in Phoenix, put down the Pittsburgh Pirates, who now have a 4-20 record on the road; the Pirates loaded the bases with nobody out in the ninth, but only runner reached home, sealing the 4-3 final score.

In San Diego, Padres' pitcher Jake Peavy set a club record with 16 strikeouts over seven innings but gave up a homer that cost him a 3-1 loss to the Atlanta Braves. The Los Angeles Dodgers beat the Colorado Rockies, 6-1, on the coast; in the first major-league game featuring two Korean-born starting pitchers, the Dodgers' Jae Seo beat his former high-school team-mate, Byung-Hyun Kim.

The Houston Astros clubbed the Nationals in Washington, 10-3. And Barry Bonds once again failed to hit his 715th home run, but his San Francisco Giants thumped the St. Louis Cardinals, 9-2.

In the latest chapter of the Yankees' perennial rivalry with the Red Sox, the New Yorkers came up short in Boston. Curt Schilling pitched eight strong innings in a 9-5 win, which put the Sox two and a half games ahead of the Yankees in the A.L. East.

The Seattle Mariners won their fourth in a row at home, 8-6, over the Baltimore Orioles - now losers in nine straight on the road. And in Toronto, the Blue Jays beat the Tampa Bay Devil Rays, 6-4.