Rookie Brad Peacock allowed one harmless single over five-plus solid innings as the Washington Nationals completed a four-game road sweep of the Philadelphia Phillies with a 6-1 triumph on Thursday.

Michael Morse belted his team-leading 28th homer with a three-run shot, and Roger Bernadina drove in a pair of runs for Washington, which has won eight straight on the road and 11 of 14 overall.

The Nationals took 10 of the 18 meetings in 2011 against the National League East champion Phillies, who mustered just four hits en route to their season-worst sixth straight loss.

Making only his second start and third career appearance, Peacock (2-0) yielded just a two-out single to Carlos Ruiz in the second inning. The 23-year-old righthander hasn't permitted a run in either start - he scattered two hits in five scoreless innings against the New York Mets on Sept. 14.

With Washington nursing a 3-0 run lead, Morse capped a four-run eighth inning with a blast to center for his first homer since Sept. 10.

Ruiz had three hits - including an RBI single in the ninth. Roy Oswalt (8-10) yielded six runs on seven hits in 7 2/3 innings to take the loss for Philadelphia.