WASHINGTON — Tanner Roark pitched seven innings, Stephen Drew and Jayson Werth homered in the fourth and the Washington Nationals defeated the winless Atlanta Braves 3-0 on Wednesday night for their fourth straight victory. Roark, who moved up a day when scheduled starter Stephen Strasburg was scratched due to illness, allowed four hits and three walks. Pitching on five days of rest, Roark (1-1) struck out four and left after 100 pitches.