PHILADELPHIA -- The suddenly slumping Phillies aren't ready to panic, but the NL East champions have some definite concerns about their recent play.
Brad Peacock, making just his second major league start, pitched 5 2/3 scoreless innings and Michael Morse hit a three-run homer to lead the Washington Nationals to a 6-1 victory over Philadelphia, completing a four-game sweep and handing the Phillies their sixth straight loss.
Carlos Ruiz had three hits and an RBI for the Phillies (98-58), who clinched their fifth straight NL East title on Saturday night but haven't won since. The season-high six-game skid is Philadelphia's longest since June 2009, and it was the first time the Phillies have been swept in a series of more than two games since last August.
"I'm concerned some but I'm not in a knee-jerk reaction," Phillies manager Charlie Manuel said. "I'm not going to panic. If you panic, you get beat."
The Phillies, as they have since Saturday's clinching win over St. Louis, need four wins to set the club's franchise record for wins in a season. That was thought to be a formality, but now the club will have to win four of its final six, beginning with Friday night's three-game series at the Mets followed by a three-game stint to close the season in Atlanta.
Philadelphia is putting an emphasis on those two series.
"We have six games left and that's definitely enough time but it's time for us to get ready for the playoffs," Manuel said. "We're sitting in a real good position but we definitely need to pick it up some."
Roger Bernadina drove in two runs for the Nationals (76-79), who have won five straight overall and eight in a row on the road. Washington needs to win five of its last six for the organization's first season over .500 since 2003.
"You want to compete against the teams in your division and we took a step in that direction," Nationals manager Davey Johnson said.
Philadelphia played all but three regulars, resting first baseman Ryan Howard, right fielder Hunter Pence and third baseman Placido Polanco, and continued to have trouble offensively. The Phillies managed just four hits off Peacock and five relievers.
Manuel said Howard, who had an anti-inflammatory injection in his sore left ankle on Monday, likely will play Friday against the Mets, rest Saturday and then play the final four games. The manager expects to have Pence, nursing a left knee strain, back in the lineup Saturday.
"We have to find a way to gather our focus," said Shane Victorino, who went 0-for-15 in the series. "The way we're playing is what people are looking at, the way we're losing, the offense not clicking. Mentally you need to find a way to get rolling in the right direction."
Roy Oswalt (8-10) allowed six runs on seven hits in 7 2/3 innings. The right-hander, who has been battling to regain his velocity since returning from a 37-game absence due to back inflammation in August, reached 94 mph on the radar gun and looked effective for much of the game.
He said Thursday's outing was the best he's felt all season, but he certainly wasn't feeling good about the team's recent play.
"We still have got to play nine innings and right now we're not playing too well," he said.
The pitcher expects an increased focus over the final six games.
"Hopefully we won't take them too lightly," he said. "The hottest team going (into the playoffs) usually wins it. Hopefully we'll start playing better."
Morse did the most damage against Oswalt with his two-out, three-run homer in the eighth that turned a close game into a rout.
"He was beating me with fastballs all night," Morse said. "I shortened up a little and hit it well."
Peacock (2-0) had his second straight impressive outing in as many major league starts, allowing only Ruiz's infield single in the second. The 23-year-old right-hander, who went 15-3 with a 2.39 ERA between Double- and Triple-A this season, hasn't allowed a run in his two big league starts over 10 2/3 innings. Peacock, who was drafted in the 41st round in 2006, walked two and struck out two while recording just two ground-ball outs.
"Peacock was outstanding," Johnson said. "He handled the pressure and made quality pitches all night."
"I put the ball in play and had good defense behind me," Peacock said. "I didn't expect this to happen this year. I had a good year and this tops it off."
The Nationals took a 2-0 lead in the third on RBI hits by Ian Desmond and Bernadina.
Desmond's double that scored Rick Ankiel should have been the third out, but Chase Utley misjudged the ball in shallow right and couldn't make the over-the-shoulder catch. Right fielder John Bowker was charging the ball, but held up to avoid a collision with Utley. Desmond scored on Bernadina's grounder that just got past the outstretched glove of first baseman Ross Gload.
The Phillies threatened in the sixth when Peacock and reliever Tom Gorzelanny walked the bases loaded with two outs, but Raul Ibanez flew out to center to end the frame. It was one of the few times the Phillies fans were able to use the rally towels given out on Fan Appreciation Night.
"That was the biggest crowd I've ever seen," Peacock said. "I got a little nervous in the sixth when they started waving the towels."
Washington added four runs in the eighth, all with two outs. Bernadina's two-out double off the wall in right-center scored Desmond, who barely had beat out an infield single. Oswalt walked Ryan Zimmerman to put runners on first and second, prompting a visit from Manuel. Morse followed by launching Oswalt's 3-2 pitch into the Phillies bullpen in center to give Washington a 6-0 lead.
Philadelphia scores its lone run with two outs in the ninth on Ruiz's single off Todd Coffey.
Utley continued his recent struggles, going 0-for-3 to finish 6-for-31 (.194) on the homestand.
"(Utley) is having a hard time finding his swing," Manuel said.
However, the manager still expects his club to be ready for the postseason.
"Our team is a bunch of guys that definitely can focus and get right back on track," Manuel said. "Six games is a lot for us to lose because we're not used to losing that many in a row. I know all of our guys and I know we're going to be ready."
Washington's Danny Espinosa went 0-for-4 and had his 10-game hitting streak snapped. Philadelphia's crowd of 45,064 was the club's 204th consecutive regular-season sellout, and the team finished the year with 3,680,718 fans. The Phillies open a three-game series against the Mets in New York at 7:05 Friday night with Philadelphia left-hander Cole Hamels (14-9, 2.80) is scheduled to face Mets righty R.A. Dickey (8-13, 3.35). Washington returns home for a three-game series against the Braves with right-hander Stephen Strasburg (0-0, 1.29) scheduled to meet Atlanta right-hander Tim Hudson (15-10, 3.19).