Nationals 6, Giants 2: Jayson Werth homered and drove in three runs to power visiting Washington to its fourth consecutive victory.

Adam LaRoche added a two-run single while Ryan Zimmerman drove in a run and saved another with a diving catch as the Nationals handed San Francisco its season high-tying third straight defeat. Tanner Roark (5-4) gave up two runs and seven hits in six-plus innings to win his second straight start and help Washington improve to 8-1 in its last nine.

Brandon Crawford delivered a run-scoring single and Pablo Sandoval added a pinch-hit RBI single for the Giants, who have dropped three in a row for the first time since April 17-19 and will look to avert a four-game sweep in Thursday's series finale. Matt Cain (1-4) lasted only five innings, allowing four runs on three hits and a season-high five walks.

The Nationals pushed across three runs in their first at-bat, capitalizing on the wildness of Cain, who walked the first three batters before LaRoche delivered a two-run single and Zimmerman added an RBI groundout. San Francisco got on the board in the fourth when Buster Posey singled and scored on Crawford's triple to the gap in left-center.

Werth belted a hanging slider into the seats in left field in the fifth for his first homer since May 14 and Zimmerman made a great grab of Crawford's sinking liner to end the sixth. Sandoval's single off Drew Storen in the seventh to cut the deficit to 4-2, but Werth plated two more runs with a two-out, bases-loaded single off Yusmeiro Petit in the ninth.

GAME NOTEBOOK: Crawford extended his hitting streak to seven games and set a career high with his fifth triple. ... The Nationals placed C Wilson Ramos on the 15-day disabled list with a strained right hamstring sustained in the ninth inning of Tuesday's game and recalled C Sandy Leon from Triple-A Syracuse. ... Sandoval was not in the starting lineup due to an illness for which he is taking antibiotics, manager Bruce Bochy said. ... The Giants traded LHP David Huff to the New York Yankees for cash considerations.