MINNEAPOLIS(AP) Joe Mauer is tired of talking about hitting .400.

Mauer had his second four-hit game of the season, Glen Perkins won his first start off the disabled list, and the Minnesota Twins beat the Pittsburgh Pirates 8-2 Tuesday night to keep up their impressive interleague play.

Mauer had three singles and an RBI double, raising his average to .429. The defending AL batting champion, sidelined in April because of a back injury, also had four hits against Kansas City on May 2.

''I just tried to keep it simple tonight,'' said Mauer, who hasn't felt well since last week in Oakland. ''I've been having a good stretch here. It's probably not going to last forever, but I'm going to try to hold onto it as long as I can.''

Mauer shakes his head in amazement when asked about hitting .400 or better, and so does his manager.

''He just keeps swinging, keeps hitting and getting it done,'' said Ron Gardenhire . ''I'm just enjoying watching him doing it. It's amazing.''

After three singles up the middle, Mauer, protecting the plate, hit a down-and-in pitch between first baseman Adam LaRoche and the bag for an RBI double in the sixth.

''He should be MVP,'' said Pittsburgh starter Paul Maholm . ''You throw him a breaking ball and he doesn't really budge. I threw some sinkers inside and he somehow inside-outs it and hits ground balls up the middle hard. You're not really getting in on him.''

Perkins (2-3) allowed two runs and seven hits in six innings, striking out four and walking one to win for the first time in seven starts since defeating the Los Angeles Angels on April 19. Perkins had been on the disabled list since May 19 because of left elbow inflammation,

Minnesota had 16 hits and improved its interleague record this year to 6-1. The Twins are 47-14 against National League teams since 2006.

Maholm (4-3), who has one win in his last 10 starts, gave up eight runs and a career-high 14 hits in five innings, and he threw two wild pitches. It could have been worse - Pittsburgh turned three double plays in the first four innings, one with the bases-loaded, and Jason Kubel was thrown out at the plate.

''It was just throwing balls thigh high rather than getting them down and getting ground balls at guys,'' Maholm said. ''I wish I could've gone out there and gotten at least through six, if not seven, with the four or five runs, but it happens.''

Pittsburgh played its first game on artificial turf since July 11, 2004, when it faced the Montreal Expos in San Juan, Puerto Rico. The span of 786 games had been the longest in the majors, according to the Elias Sports Bureau.

Nyjer Morgan homered for the Pirates in the third, his first home run since Sept. 25, 2007. Andy LaRoche nearly homered in the fifth, but Delmon Young robbed him with a great catch at the fence.

''Against an offensive team like this we need to score more than two runs,'' said Pittsburgh manager John Russell .

With the score 2-all, Minnesota went ahead in the third on Justin Morneau 's RBI single and a run-scoring double-play grounder by Kubel. Minnesota hit into five double plays in all.

Joe Crede was credited with an RBI double in the fifth when rookie center fielder Andrew McCutchen lost a ball in the Metrodome roof.

NOTES: Struggling reliever Jesse Crain was optioned to Triple-A Rochester to make room for Perkins, leaving the Twins with six relievers. ... After the game, Minnesota put outfielder Denard Span on the 15-day disabled list, and recalled outfielder Jason Pridie from Triple-A Rochester. Span, out since June 9 because of a right inner ear problem that has caused dizziness, has been prescribed medication for a virus that attacks a nerve that sends signals, such as balance, from the ear to the brain. ... Charlie Morton was scheduled to start for Pittsburgh, but was pushed back to Saturday because of a strained left hamstring. Because of Monday's off-day, the rest of the staff is pitching on its usual rest.