Archie Bradley (5-1) allowed a run in the top of the ninth but got the win.
Josh Bell tripled and drove in two runs for the Nationals, who have lost five straight and 11 of 14.
Joe Ross pitched five scoreless innings, allowing three hits with four strikeouts and two walks, in his return to the Washington rotation after being sidelined since July 4 due to right elbow inflammation.
Spencer Howard breezed through three scoreless innings of one-hit ball before running into trouble in the fourth. Bell atoned for his first-inning blunder, when his lackadaisical play loping to the bag at first base allowed Realmuto to reach on an infield single, by tripling home the first run.
Phillies ride momentum from walk-off into rematch with Nats
pittsburghstar.com - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from pittsburghstar.com Daily Mail and Mail on Sunday newspapers.
Washington Nationals pitcher Stephen Strasburg to have season-ending neck surgery
espn.com - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from espn.com Daily Mail and Mail on Sunday newspapers.
Stephen Strasburg to undergo surgery, ending season
washingtontimes.com - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from washingtontimes.com Daily Mail and Mail on Sunday newspapers.