The two-time defending NL champions are off to a 6-1 start, their best since opening the 1993 pennant-winning season 7-1.
Cole Hamels (2-0) earned the win despite another so-so effort. He allowed four runs and six hits in 5 2-3 innings. The lanky left-hander is trying to bounce back following an inconsistent year after a dominant postseason in 2008.
Playing without Jimmy Rollins, a late scratch after straining his right calf, the Phillies continued their torrid hitting.
They're averaging 7.1 runs and 11 hits per game.
The Phillies celebrated the franchise's seventh pennant during a pregame ceremony, then won their first home opener since 2005. Led by the Phanatic, their furry green mascot, players entered the field from Ashburn Alley behind the stands in left-center field and walked through the crowd and onto a red carpet that stretched from the warning track to the infield.
Manager Charlie Manuel raised the 2009 NL championship flag on the concourse behind the brick batter's eye. Players were introduced to rousing ovations and the U.S. Navy parachute team delivered the first balls.
Josh Willingham hit a solo homer and losing pitcher Jason Marquis had a two-run double for the Nationals.
Rollins, the three-time All-Star shortstop and 2007 NL MVP, got hurt while running in the outfield during pregame warmups. He had already been introduced in the starting lineup.
All-Star right fielder Jayson Werth left in the sixth because of soreness in his left hip. There was no immediate word on the extent of the injuries to both players.
Marquis (0-2) allowed seven runs - six earned - and six hits in 4 1-3 innings. The right-hander, who signed a $15 million, two-year contract with Washington as a free agent, was an All-Star with Colorado last season.
The Phillies came back from a 4-0 margin by scoring twice in the fourth and chased Marquis with five in the fifth. Carlos Ruiz started the fifth with a single. Hamels tried to sacrifice and reached safely when catcher Ivan Rodriguez's throw to second bounced into center field for an error.
Juan Castro, filling in for Rollins, hit an RBI double to deep left-center. Polanco followed with a two-run single to right-center to put the Phillies ahead 5-4. Utley hit a two-run shot off the foul pole in right to make it 7-4.
Chad Durbin, Jose Contreras, Danys Baez and Ryan Madson combined for 3 1-3 innings of scoreless relief for Philadelphia. Madson earned his second save in as many tries.
Willingham homered leading off the second. Washington added three runs with two outs in the fourth. Hamels nearly escaped trouble after giving up a single to Cristian Guzman and nicking Adam Dunn's jersey with a pitch. He struck out Willingham on a 3-2 pitch, painting the outside corner with a 92 mph fastball. Hamels blew a fastball past Ian Desmond for the second out, butt Rodriguez followed with an RBI single to make it 2-0.
After Adam Kennedy walked to load the bases, Marquis lined a two-run double out of the reach of leaping third baseman Polanco.
The Phillies answered with two in the bottom half. Polanco hit a one-out single, Utley walked and Ryan Howard hit an RBI single.
Nationals manager Jim Riggleman went out to talk to Marquis and was ejected by plate umpire Paul Schrieber, who went to the mound to speed up the conversation. Werth drove in a run with a grounder to third to cut it to 4-2.
Hamels helped the Phillies win their second World Series title in '08 and earned MVP honors in the NLCS and World Series. But he struggled to match that success last year, going 10-11 in the regular season and 1-2 in the postseason.
NOTES: The Phillies had their 43rd consecutive sellout in the regular season. ... Phillies first-base coach Davey Lopes rejoined the team following the death of his brother earlier this month.
