Mauricio Dubon hit a walk-off RBI single in the bottom of the ninth to lift the Astros over the Baltimore Orioles 2-1 at Minute Maid Park. Dubon and Jeremy Pena each drove in a run to help Houston avoid a three-game sweep at home. Ryan Pressly earned his fourth win of the year after closing out the game with one scoreless inning of relief. The Astros hold a half-game lead over the Rangers and Mariners atop the AL West at 85-and-68. Houston will host the Kansas City Royals tomorrow night.