Updated

PHILADELPHIA (Reuters) - The Philadelphia Phillies remained on the heels of the front-running Atlanta Braves in the N.L. East by edging the Washington Nationals 1-0 Friday.

The victory kept the Phillies 2.5 games back of the Braves, after Atlanta stopped the Chicago Cubs 5-3 earlier Friday on a three-run triple in the ninth inning by Rick Ankiel.

Washington was unable to capitalize on its chances against Roy Halladay, who improved to 16-8 despite allowing eight hits and three walks in seven innings while striking out five.

It marks the fifth time that Halladay has allowed one run or less in his last six starts, all of them victories. The Nationals outhit Philadelphia 10-4 but they left runners on base in every inning.

Chase Utley scored the only run of the game after leading off the third inning with a walk and scoring two batters later on an RBI double by Raul Ibanez.

Jason Marquis (0-6) pitched five innings allowing one run on four hits and four walks while striking out one in the loss for Washington.

(Reporting by Mike Mouat in Windsor, Ontario. Editing by Steve Ginsburg)