HOUSTON - Jason Castro hit a three-run homer in the seventh inning and the Houston Astros beat fading Pittsburgh 4-1 Saturday night, handing the Pirates their fifth straight loss.
The Pirates fell 6 1/2 games behind St. Louis for the last NL wild-card spot. Pittsburgh has lost 17 of its last 21 and dropped to 74-77, moving closer to its 20th straight losing season.
Rookie Dallas Keuchel (3-7) pitched seven strong innings for the win.
Castro hit his third home run of the season, connecting for a tiebreaking shot off Kevin Correia (11-10).
Pittsburgh manager Clint Hurdle was ejected in the second inning for arguing a call at first base.
Hurdle argued with first base umpire Tim Timmons, who moments earlier called Michael McKenry out on a throw from first baseman Brett Wallace to Keuchel. The call came after Gaby Sanchez hit a tying home run.
Right-handers Hector Ambriz and Wilton Lopez each pitched scoreless innings to secure the win. Lopez got his seventh save.
The Astros scored in the first on a double by Scott Moore and a single by Wallace.
Keuchel four hits for his second win in as many starts. He struck out five and walked one.
Correia was equally impressive through six innings for the Pirates -- he tied a career high with nine strikeouts -- but ran into trouble in the seventh.
Jed Lowrie led off with a single and pinch runner Tyler Greene made it safely to second on an error by shortstop Clint Barmes on Matt Dominguez's grounder. Castro's homer soared just high enough to clear the right-field wall and the glove of Garrett Jones.
This marked the third time Correia has struck out nine, most recently on July 18, 2010 against Arizona. ...
The Pirates finished with three errors.
NOTES: Seven-time Cy Young winner Roger Clemens was at Minute Maid Park as many former Astros stars helped celebrate the 50th anniversary of the franchise.