HOUSTON — If these are Roy Oswalt's last weeks with the Houston Astros, he's certainly going out in style.

Oswalt, who requested a trade earlier this season, allowed only a first-inning single to Pine-Richland graduate Neil Walker, Lance Berkman provided the power with two home runs and the Astros completed a three-game sweep of Pirates with a 2-0 win Thursday.

Oswalt (6-10) struck out eight and walked two.

Carlos Lee singled and Pirates starter Ross Ohlendorf walked Hunter Pence after Berkman's second homer, prompting a short visit to the mound by Pittsburgh coaches. Ohlendorf (1-7) pitched out of trouble by retiring the next three batters, striking the first two out.