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10/06/11 7:52 PM ET

Perez rips walk-off double in Rafters' win

Early two-run homer by Ruf doesn't hold up for Scorpions

For six innings Thursday, the Scottsdale Scorpions' pitching staff seemed nearly untouchable. But at the end, Hernan Perez made sure the Salt River Rafters broke through when it mattered most.

The 20-year-old second baseman doubled home fellow Tigers prospect Dixon Machado in the bottom of the ninth inning as the Rafters overcame the Scorpions for a 3-2 walk-off win.

Signed as a non-drafted free agent in 2007, Perez hit .258 with eight homers and 69 runs scored for Class A West Michigan in 2011. He finished Thursday's game 3-for-5 and was also the first player to touch home, coming around to score on a bases-loaded groundout by Nolan Arenado (Rockies) in the first.

The Scorpions got two in the second on a two-run homer by Darin Ruf (Phillies), who slugged 17 long balls for Class A Advanced Clearwater this year. The 25-year-old first baseman wasted no time finding his old stroke, going deep on the sixth pitch he saw in his first at-bat off starter Andrew Oliver (Tigers).

Scottsdale hung on to a 2-1 lead until the eighth, when Alex Castellanos (Dodgers) tied the game with his first homer off the Phillies' Colby Shreve. Perez finished the game off in the ninth, smacking his double off Daniel Tillman (Angels).

Scorpions starter Sammy Solis (Nationals) held the Rafters to one run on two hits over three innings before manager Arnie Beyeler pieced together four shutout innings from the bullpen.

Oliver went 1 2/3 innings for Salt River, allowing two runs on four hits. Five relievers combined to shut out Scottsdale over the final 7 1/3 frames, yielding five hits and six walks while striking out four. The Dodgers' Josh Wall (1-0) earned the win after giving up a hit over the final 1 1/3 innings.

Bryce Harper, MLB.com's No. 2 prospect, went 0-for-5 with a strikeout in the cleanup spot for Scottsdale. The first overall pick in 2010 is hitless in his first seven Arizona Fall League at-bats.

David Heck is a contributor to MLB.com. Danny Wild contributed reporting to this story. This story was not subject to the approval of Major League Baseball or its clubs.