Placido Polanco, Wilson Valdez and Raul Ibanez drove in two runs apiece and Roy Oswalt threw seven scoreless innings for his third consecutive win, leading the Philadelphia Phillies to a 6-0 victory over the Washington Nationals on Sunday.

The Phillies remained 2 1/2 games behind NL East leader Atlanta, which beat the Chicago Cubs 16-5, and moved two games ahead of San Francisco in the wild card race after the Giants lost 9-0 to St. Louis.

Oswalt (9-13) held the Nationals to five hits and a walk while striking out eight, and he might have stayed in the game if not for a long rain delay after the top of the seventh inning.

Polanco drove in runs with a sacrifice fly in the first and a single in the third to stake Oswalt to a 2-0 lead. Valdez added a two-run single in the sixth.

Ibanez hit his 12th homer after the delay, a two-run shot off reliever Craig Stammen.

Nationals starter Scott Olsen (3-6) allowed four runs on nine hits over six innings, losing his fourth consecutive start.