Ben Francisco hit two of Philadelphia's four homers Wednesday night, and a lineup filled with reserves led the NL East champion Phillies to a 7-1 victory over the last-place Nationals in Washington's home finale.

Only two regulars started for Philadelphia, which is 95-64 and already was assured of home-field advantage throughout the postseason, as manager Charlie Manuel gave key cogs such as Ryan Howard and Chase Utley the night off. Mike Sweeney and Francisco hit consecutive homers off Ross Detwiler (1-3) to open the second inning.

John Mayberry added a three-run shot in the fourth, and Francisco's second homer of the night, a two-run drive, came an inning later.

Joe Blanton (9-6) gave up one unearned run and three singles in seven innings.

In what might have been Adam Dunn's final game at Nationals Park as a member of the home team, the slugging first baseman went 0 for 4 with four strikeouts. He leads Washington with 38 homers and 103 RBIs and can become a free agent this offseason.

"We need to get a four-hole hitter that plays first base. We understand that. We want it to be Adam Dunn," Nationals general manager Mike Rizzo said. "But if it isn't, we need to address that situation."

When Dunn led off the ninth inning, he was greeted by a standing ovation from most of the announced crowd of 20,026.

The Nationals drew a total of 1,828,066 fans in 2010. That's an average of 22,569 — up about 135 per game from 2009 — at 40,000-plus-capacity Nationals Park.

The first hit allowed by Blanton was to Nyjer Morgan leading off the fourth. Morgan wound up making it to third — but was stranded there — after first baseman Sweeney botched a throw to second trying to complete a double play and was charged with an error.

It was an eventful evening for Sweeney, who stumbled and tumbled to the infield dirt while making a throw to Blanton covering the bag on a groundout by the Nationals' second batter of the game.

Sweeney was making his 11th start of the season at first base, and his homer was his eighth. He is heading to the playoffs for the first time in his 16-season big league career, the longest drought among active players.

Francisco made his 17th start of 2010 in left field and hit his fifth and sixth homers. It was his fourth multihomer game in the majors, first with the Phillies. Francisco also made a sliding catch of a sinking shot to end the fifth inning.

Mayberry made his first start this season — his eighth appearance — and collected his first homer since June 30, 2009.

Detwiler gave up all four homers in his 4 2-3 innings. He allowed seven runs and seven hits.

Phillies shortstop Jimmy Rollins and center fielder Shane Victorino — both expected to be in the starting lineup next Wednesday, when Philadelphia opens its NL division series at home — went a combined 0 for 8 before leaving in the bottom of the seventh.

Manuel said he plans to use most of his regulars in the last regular-season series, a three-game set that begins Friday at the Atlanta Braves, who are chasing the NL wild-card spot.

"I'm not playing Howard or Utley tonight, but I'm going to play them in Atlanta some," Manuel said. "How much, I don't know yet, but I might play them the biggest part of the games there. We're going to play some front-line players there."

NOTES: Phillies 3B Placido Polanco is expected to rejoin the team in Atlanta after getting a cortisone shot in his left elbow. ... Victorino will leave the team on Thursday's off day to fly home and be with his wife, who is about to give birth. Victorino wasn't sure if he'd miss Friday's game. ... Manuel said LHP Cole Hamels would likely get a start against Atlanta, but would be limited to two or three innings. ... Rizzo said acquiring a "front-of-the-rotation" pitcher will be his "No. 1 priority going into the offseason." ... The Phillies are 21-6 in September.