Philadelphia pounded out 16 hits, but was unable to score again after establishing a 5-1 lead through four innings.
J.A. Happ (3-0) allowed all three Washington runs in 5 1/3 innings, and then turned things over to the bullpen. Four relievers combined to allow three hits and no runs over the final 3 2/3, and Lidge struck out two in the ninth for his 10th save.
Ibanez broke a 1-1 tie with a two-run single in the third and then scored on a triple by Pedro Feliz.
Ross Detwiler (0-1), making his third major league start, took the loss with a four-inning stint. He allowed five runs on 10 hits.
The Nationals, with just 13 wins to their credit all season, saw their current losing streak reach four games.
Copyright 2009 by United Press International.