MINNEAPOLIS (AP) — Prince Fielder broke open a scoreless game with a two-run double in the sixth inning, the spark that Rick Porcello and the Detroit Tigers used to beat the Minnesota Twins 4-0 on Friday night.

Victor Martinez and Jhonny Peralta followed Fielder’s soaring drive with RBI doubles of their own, ending the night for Twins starter Scott Diamond (4-6). Even better for the Tigers was that the four-run cushion kept sputtering closer Jose Valverde out of a pressurized save situation.

Porcello (4-3) didn’t need much relief. The right-hander breezed through seven scoreless innings, allowing just two singles and one double without a walk. He struck out five and gave the Tigers their 19th quality start (of six innings or more and three runs or less) in the last 20 games.

Despite his status as the afterthought of this stacked rotation behind Justin Verlander, Max Scherzer, Anibal Sanchez and Doug Fister, Porcello has shined in his last four appearances. He’s 2-1 with 30 strikeouts in 27 innings and just 15 hits, five runs and four walks against him during that stretch.

Diamond matched Porcello frame for frame until he walked Austin Jackson, the leadoff man back in his familiar spot after missing the last month because of a pulled left hamstring, with one out in that decisive sixth. Torii Hunter advanced Jackson with a groundout, and Miguel Cabrera was intentionally walked.

Fielder made the Twins pay. With one of those huge upper-cut swings, he smacked a 2-0 curveball high off the towering right-field wall to put the Tigers in front. Cabrera ran through the stop sign by third base coach Tom Brookens, whose arms were still straight up in the air as the big slugger chugged home without a throw.

Valverde came in for the ninth after Drew Smyly and Joaquin Benoit collaborated on a scoreless eighth. Valverde ominously walked Joe Mauer to start the inning, but Ryan Doumit followed with a double-play ground ball. Josh Willingham was grazed by a pitch, but Justin Morneau struck out looking to end the game.

In Valverde’s previous six appearances, he allowed 10 hits, seven runs and five homers over 5 1-3 innings while blowing two of his five save opportunities.

Valverde gave up a tying, two-run homer to Kansas City’s Lorenzo Cain with two outs in the ninth inning on Wednesday, a game the Tigers lost in the 10th. Detroit’s bullpen, the one glaring area of concern on this otherwise-championship-caliber club, has a 4-12 record with eight squandered saves in 22 chances.

Manager Jim Leyland bristled at a question about whether Valverde was still the closer, angrily lacing his answer with expletives before eventually affirming the veteran right-hander’s status.

“We’re going to use Jose Valverde until we decide Jose Valverde can or can’t do it or we’ve got somebody else better,” Leyland said.

The skipper tried to suggest too much attention has been fixated on his relievers, noting the Tigers have had some recent trouble scoring. While losing two of three to the Royals they had seven runs in 28 innings. But the Tigers still have the best batting average in baseball, at .281 entering the night.

The Twins have seen marginal improvement with their patchwork rotation recently, with a collective 2.87 ERA by their starters over the previous 10 games. But Diamond, the only one who pitched well enough in 2012 to warrant a spot in this year’s group, has been the outlier.

The left-hander, who was replaced with two outs in the sixth, gave up five hits and two walks with just one strikeout. The six scoreless innings he pitched on June 2 fueled his lone victory of the last seven turns. That’s also the only time in that span he finished six innings.

Hitting has quietly been a bigger problem for the Twins lately. They have just 13 runs in their last seven games.

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