PITTSBURGH — Most games decided by six runs don't feature a pitchers duel. This one did, even though it ended with a familiar finish: Johan Santana won again and Oliver Perez lost again.

Minnesota turned two infield grounders and a single by Mike Redmond into the decisive run in a four-run eighth inning and another loss for Perez against a Cy Young Award winner, and the Twins finished off a three-game sweep by beating the Pittsburgh Pirates 8-2 Sunday.

With Justin Morneau adding a three-run double in the eighth, the Twins won their seventh in a row and ninth in 10 games. They have swept their last two series, against the Red Sox and Pirates, to reach the .500 mark (34-34) for the first time since they were 7-7.

"Everything right now is working pretty good, and it seems like we've put everything together and we're more consistent from the starting rotation to the bullpen," Santana said. "It's about being consistent in everything we do."

Santana (7-4), the 2004 AL Cy Young Award winner, held the Pirates to a run and five hits over seven innings and is 7-1 in 11 starts since losing his first three. He had five strikeouts and no walks, giving him 91 strikeouts and seven walks in 79 innings in those 11 starts.

"Perez was matching everything Santana threw up there," Twins manager Ron Gardenhire said. "We finally broke through with some big at-bats. But it was a very well-pitched game, and that was pretty impressive."

The final score didn't indicate how well Perez pitched in his second consecutive loss to a Cy Young Award winner — he was beaten 2-1 Tuesday as the Cardinals' Chris Carpenter struck out 13. Perez (2-9) permitted only two singles and retired 14 of 15 batters before Torii Hunter homered into the left-field seats with two outs in the seventh for Minnesota's first run.

"I think the momentum changed when Torii hit that home run," Redmond said. "It was like, 'Hey, we can get this guy,' and sure enough we did."

Notes: Bay hit his 20th homer in the ninth. ... Minnesota's winning streak is its longest since a nine-game run Sept. 7-16, 2004. ... The Twins are 5-1 and the Pirates are 1-5 in interleague play. ... Morneau is 17-for-40 (.425) during his hitting streak. ... The Pirates lost their fourth in a row and are 1-5 on a seven-game homestand that ends Monday.