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Brandon Allen had an impressive 2010 debut with Arizona, hitting a grand slam and making several rangy catches in left field to help the Diamondbacks send the reeling San Diego Padres to their seventh straight loss, 5-2 on Wednesday.

Called up from the minors before the game, Allen made a running, leaping catch against the fence on Chase Headley's slicing fly to the corner in the fourth inning and had an in-the-gap grab in the fifth to back Barry Enright (6-2). Allen punctuated his return to the majors in the seventh, hitting his first career grand slam to right off Luke Gregerson (3-7).

San Diego's Miguel Tejada broke a 4-for-26 slump with a solo homer in the fourth inning, but had an error on a potential double-play ball to set up Allen's grand slam.

Chris Young hit his 23rd homer, Enright allowed two runs on nine hits in seven innings and Juan Gutierrez pitched the ninth for his sixth save to help Arizona complete a three-game sweep of the NL West leaders. The Diamondbacks have won six of seven.

The Padres started the day with a four-game lead over San Francisco, but another loss at last-place Arizona wasn't what they wanted heading into a 10-game homestand against three division opponents.

Ace-in-the-making Mat Latos figured to be the slump-stopper and did his part, holding the Diamondbacks to one run and four hits over six innings while matching a career high with 10 strikeouts.

The right-hander made one mistake: a 3-1 down-the-pipe fastball that Young turned on and turned into a curling solo homer off the foul pole in left that tied it 1-all.

That was it, though. Latos didn't come out for the seventh, lifted in the top half for a pinch hitter after becoming the first pitcher to allow two earned runs or less in 14 straight starts since Greg Maddux did it with Atlanta from 1993-94.

Will Venable, who replaced Latos, put San Diego up 2-1 with a run-scoring single in the seventh, but Gregerson couldn't hold the lead.

The right-hander walked Mark Reynolds leading off the bottom half, gave up a single to Gerardo Parra after Tejada's error at shortstop, then watched Allen's drive sail out to right.

The offense was expected from Allen. The slugging prospect hit 25 homers with 86 RBIs in 107 games with Triple-A Reno this season. He's been a work-in-progress at first base, though, and his big league chances were diminished when the Diamondbacks signed Adam LaRoche in the offseason.

Arizona started occasionally sending Allen out to left in the minors and he played well enough to earn a September call-up, getting a start in his first game back. The rookie responded with several nifty grabs in the outfield and earned a curtain call with his shot to right that put the D-backs up 5-2. Not a bad start for a player who hit .202 and had 40 strikeouts in 32 games as a first baseman with Arizona last season.

Notes: Arizona failed to score six runs for the first time in seven games. ... The last pitcher to allow two earned runs or less in 14 straight starts in one season was Houston ace Mike Scott in 1986.