Oswalt was supposed to start for the Phillies on Friday night, but after torrential rain arrived in the first inning, the game was delayed by 2 hours, 22 minutes, and he was scratched.
The Phillies, winners for the 81st time this year, scored twice in the fourth and three times in the sixth as Oswalt (6-7) struck out nine - the most since joining Philadelphia last July. He walked one and had runners on in every inning but the second and third.
Michael Stutes worked the ninth to complete the Phillies' 15th shutout of the season.
Contrasted with the nasty Friday weather, this beautiful night drew a Nationals Park record crowd of 44,685 - most of them cheering for Philadelphia and booing Jayson Werth.
As he took the field for the first inning, Werth tipped his cap to the jeering fans, one of whom carried a sign that read: "Was it Werth it?" - a reference to his seven-year, $126 million deal that convinced him to leave the Phillies and join the Nationals.
In the fourth, John Mayberry Jr. singled with two outs. He tried to steal, but John Lannan threw to Michael Morse at first. Morse's throw arrived at second ahead of Mayberry but Ian Desmond dropped the ball. Mayberry was safe. Carlos Ruiz walked, and Valdez tripled them both in.
Oswalt struck out five batters in the first three innings, and was helped enormously by Mayberry, whose throw to the plate nailed Ryan Zimmerman, who tried to score on Werth's single in the fourth.
Pence led off the sixth inning with a long, high home run to left field - his 15th. Philadelphia is 15-4 since his arrival in a trade from Houston.
Mayberry and Ruiz followed with singles, and Collin Balester replaced Lannan (8-9). After Valdez hit into a fielder's choice, Oswalt bunted to first. Instead of tagging the pitcher for the second out, Morse tried to get Ruiz at third. The throw was not in time, and the bases were loaded. Rollins singled to score Ruiz and Valdez for a three-run inning, and a 5-0 lead.
Lannan, now a woeful 1-12 against the Phillies, was charged with five runs - three earned in his five-plus innings.
NOTES: Philadelphia manager Charlie Manuel said RHP Cole Hamels' bullpen session on Saturday went well. Hamels missed a start with an inflamed left shoulder. He'll throw again in the bullpen and is scheduled to start on Aug. 26 against Florida. ... Phillies RHP Ryan Madson, who tied his career high by allowing six runs against the Nationals in Friday's ninth inning, was unavailable on Saturday. ... Philadelphia OF Shane Victorino returned after serving a two-game suspension for his part in the Aug. 5 fight in San Francisco. ... Phillies 3B Placido Polanco (sports hernia) said he hopes to come off the disabled list on Monday. ... Washington manager Davey Johnson said that there's no need for a September return for C Ivan Rodriguez (right oblique strain), who hasn't played since July 6. "I'm not really concerned about it. It's not like he has to prove anything to me or the organization. The only thing I'm concerned about is him getting healthy and not rushing, which he has a tendency to do," Johnson said. ... RHP Roy Halladay (15-5) will start for the Phillies on Sunday. He's 3-0 this season and 11-1 in his career against Washington. ... RHP Chien-Ming Wang (2-2) is the Nationals' starter. Johnson said he hopes that Wang, who missed more than two years after shoulder surgery will strongly consider signing with the Nationals. "Hopefully, he enjoys pitching here," Johnson said. "If he chooses to go elsewhere, I think it's been good for both parties."
