Kansas City, Mo. ? The Kansas City Royals cooled off the Oakland Athletics rather quickly.

Mike Sweeney hit a go-ahead, two-run double in a four-run eighth inning, and the Royals beat the A’s, 5-3, Friday night to complete a doubleheader sweep.

Kansas City won the opener, 7-1, as Luke Hudson stymied Oakland on five hits in seven innings. The A’s had just three hits in the second game and nine in the doubleheader.

Coming in, the Athletics had won six straight, 13 of 14 and 17 of 20. Oakland, which began the day with a six-game AL West lead, had won 12 in a row at Kansas City since May 30, 2003, outscoring the Royals 95-30 in that span.

“I don’t know what it is,” Royals manager Buddy Bell said between games. “I don’t think we play any different.”

The Royals last swept a doubleheader Sept. 20, 2005, when they hosted the Detroit Tigers. Oakland played its first doubleheader since June 8, 2003, when it was swept at Philadelphia. The A’s have not swept a twinbill since Aug. 22, 1998, against Detroit.

In the second game, Frank Thomas hit a two-run homer in the eighth off Ambiorix Burgos (3-5) for a 3-1 lead. Thomas’ 26th homer this season gave him 1,537 RBIs, tying Joe DiMaggio for 39th place.

Andres Blanco and David DeJesus singled off Justin Duchscherer in the bottom half, and Esteban German hit a run-scoring grounder.

Huston Street relieved, Mark Teahen singled and Sweeney doubled to left, taking third on the throw home. Emil Brown followed with a sacrifice fly off Street, who blew a save for the eighth time in 37 opportunities.

Joe Nelson pitched the ninth for his second save in as many chances. Kansas City starter Jorge De La Rosa gave up two hits and four walks in five innings.

Hudson (6-4) combined with Jimmy Gobble and Joel Peralta on a six-hitter in the opener.

Ryan Shealy had three hits and two RBIs for Kansas City, which swept a three-game series at home against the Boston Red Sox from Aug. 8-10.