Even the absence of a couple of starters didn't slow down game series with the hosting Washington Nationals.

The chips seemed slightly stacked against the Phillies in their rubber match with the Diamondbacks yesterday. With third baseman Placido Polanco already on the disabled list due to a sports hernia and All-Star center fielder Shane Victorino serving the first of a reduced two-game suspension for his actions against the Giants on Aug. 5, slugging first baseman Ryan Howard (sore right hand) and catcher Carlos Ruiz (bruised groin) were both held out of the lineup due to injury.

The reserves stepped up, with Wilson Valdez driving in the game's first run with a double in the second inning and John Mayberry Jr. connecting on a two- run homer one frame later en route to a 4-1 victory. And while backup catcher Brian Schneider didn't do much at the plate, the Phils are 24-3 in games he starts this season, winning each of the past 16.

Philadelphia has won 14 of its past 16 series and leads Atlanta by 8 1/2 games for first place in the National League East. The Phillies upped their MLB- leading record to 80-42, the fastest they have reached the 80-win mark since doing so in 121 games in 1976.

More good news is that the Phils could have both Howard and Ruiz back in the lineup tonight as starter Roy Oswalt tries to record back-to-back winning starts for the first time since season's opening month.

Oswalt recently returned from a disabled list stint caused by a back issue and in his second game since the DL on Saturday, he halted a three-start losing streak by yielding three runs over seven innings of an 11-3 victory over the Nationals. It was the right-hander's first win since June 12 and manager Charlie Manuel said Oswalt started off throwing almost exclusively fastballs before working in his changeup, breaking ball and slider.

"Overall, my fastball is coming back and I feel healthy," said Oswalt. "Any time you get a win, it's great."

The 33-year-old improved to 5-7 with a 3.84 earned run average in 15 starts this season and will try to win consecutive outings for the first time since he began the season 2-0 on April 3-9. He has split two meetings with the Nationals this year and is 6-4 with a 3.17 ERA against the franchise lifetime.

Washington's Livan Hernandez is set to face the Phillies for a fifth time in 2011, going 2-1 with a 3.12 ERA in the previous meetings. The righty beat the squad on Friday in Philadelphia, allowing only one unearned run over 6 2/3 innings. The veteran also hit a pair of RBI singles in his longest outing since July 2.

Even with last week's success, Hernandez has struggled against Howard, with the former MVP going 6-for-12 off him this year with a pair of home runs.

Hernandez, 36, is 7-11 with a 4.21 ERA in 25 starts this year and has a 3.27 ERA in 12 outings at home in that time.

The victory by Hernandez was part of a three-game win streak over the Phillies for the Nationals that ended the following night in Oswalt's outing. Overall, Philadelphia has won 31 of the past 42 meetings, going 14-8 as the visiting team in that span.

Washington plays the middle leg of its 10-game homestand that it began with a series victory over Cincinnati. The Nationals won yesterday's rubber match, 3-1, on the strength of Jesus Flores' solo homer and a two-run single by Jonny Gomes against his former club.

Flores drove in the 100th RBI of his career with his fifth-inning shot and Jordan Zimmermann earned the win with 5 2/3 scoreless innings.

"I thought he held his poise and threw the ball good," Nats manager Davey Johnson said. "I was very pleased with the six innings he gave us."

Drew Storen worked around a pair of ninth-inning singles to record his 33rd save of the season.