Boston ? Kansas City has the worst record in baseball this season yet keeps beating recently contending Boston, which has the worst record since Aug. 5.

The Royals won their fifth straight game over the Red Sox when Jeff Keppinger’s three-run homer broke a tie in the six-run 12th inning that gave Kansas City a 10-4 victory Saturday night.

“The Sox are still a powerhouse, one of the most feared teams in baseball,” Kansas City’s Mike Sweeney said. “To beat them two straight here is a huge feat. I can’t ever remember playing as well as we have against the Red Sox.”

Kansas City improved to 54-89 one night after winning 10-9 with two runs in the ninth. Boston fell to 75-67, and is 10-24 since Aug. 5.

The Royals “might not have the record that dictates they should beat us, but they have good players over there,” Boston’s Coco Crisp said.

Kansas City had squandered leads of 2-0 and 4-2 one night after blowing an 8-3 lead when Boston also scored six runs in one inning, the eighth. Saturday, David DeJesus started the winning rally with a leadoff double off Craig Breslow (0-1).

Manny Delcarmen replaced Breslow and retired Esteban German before walking Mark Grudzielanek intentionally. Then Keppinger, who entered the game in the 10th as a pinch runner, went to the opposite field and just cleared the low fence 302 feet down the right-field line.

Keppinger was obtained from the New York Mets organization July 19.