While the Washington Nationals are getting closer to securing the first division title in franchise history, the Philadelphia Phillies ' chances of reaching the postseason for the sixth straight year are dwindling.

Coming off a tough weekend, Philadelphia looks to get back on track behind Cole Hamels on Tuesday night when it hosts the NL East-leading Nationals in the opener of a three-game series.

The Phillies (77-76) extended their winning streak to four and won for the 12th time in 15 games Friday night by posting a 6-2 victory over visiting Atlanta. The five-time defending NL East champions, though, lost 8-2 on Saturday and 2-1 on Sunday to put a serious dent in their pursuit of the NL's second wild-card spot.

"Obviously, we're running out of games," Sunday's losing pitcher Cliff Lee told the Phillies' official website. "We really need to win every game. Today was big, but there's nothing we can do now.

"Hopefully we can win (Tuesday), and basically we've almost got to win out and hope the guys ahead of us lose. We've put ourselves in a position we really don't want to be in, but there's nothing we can do about it now except for come and try to win (on Tuesday)."

A series against a Washington team that owns the best record in the majors at 93-60 may not seem like an ideal opportunity for the Phillies to make up ground, but they've won three straight meetings and six of the last seven.

Hamels (15-6, 3.05 ERA) has pitched well in the season series, posting a 1.17 ERA in going 2-1 over three starts. He's 12-5 with a 2.48 ERA lifetime against the Nationals.

The left-hander will be trying for the second time to set a career high in wins. Hamels allowed two runs and struck out a season high-tying 10 over six innings Wednesday in New York, where Ryan Howard 's two-run homer with two outs in the ninth gave the Phillies a 3-2 win.

Hamels is 4-0 with a 2.50 ERA in eight starts since losing 3-0 in Washington on Aug. 2, when he gave up three runs and struck out nine over seven innings.

Ross Detwiler (10-6, 3.10) outdueled Hamels in that game, allowing three hits in seven innings in his only start against Philadelphia this season, and they will square off again Tuesday.

The Washington southpaw, who is 3-0 with a 2.43 ERA in his last five starts, will now look to get his team closer to the division title. The Nationals have already secured the franchise's second postseason berth and first since the Montreal Expos came within a game of the World Series in 1981.

Washington beat Milwaukee 12-2 on Monday to reduce its magic number for winning the NL East to five. The franchise has never won a division title - Montreal owned a 74-40 record and led the East by six games in 1994 before a strike wiped out the rest of the season and the playoffs.

"We still have a little ways to go, but if we keep playing baseball the way we've been playing, hopefully it'll happen soon," said third baseman Ryan Zimmerman , who had three hits and four RBIs on Monday.

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