Wesley Wright gave up a walk-off homer to Pittsburgh's Drew Sutton with one out in the bottom of the ninth as the Astros lost for the sixth straight game, this time 8-7 to the Pirates.
The Astros had tied the game at seven in the top of the ninth on pinch-hit RBI-double from Jason Castro.
Lucas Harrell gave up five earned runs over five innings in the start. Houston led 6-2 entering the bottom of the sixth, but the final three runs off Harrell came in the sixth inning, when he was pulled without recording an out. The Pirates scored two in the seventh to take a 7-6 lead.
Jordan Schafer went 2-for-5 with two RBIs, while Jed Lowrie went 2-for-3 with two RBIs and a run scored.