SAN FRANCISCO -- Even with standouts Bryce Harper and Gio Gonzalez on the disabled list, the Washington Nationals are shutting down the team with best record in the baseball and taking over the title as the league's hottest club.
Jayson Werth hit his first home run in almost a month and drove in three runs, and the Nationals capitalized on Matt Cain's erratic start to beat the San Francisco Giants 6-2 on Wednesday night for their fourth consecutive victory.
"We kind of got Cain on the ropes early, got his pitch count up, got some big hits early to kind of set the tone for the game," Werth said. "It's hard to recover from."
Cain (1-4) walked the first three batters he faced before Adam LaRoche's two-run single during a three-run first inning. Werth's solo shot in the fifth and two-run single in the ninth provided the rest of the pop for the Nationals, who have won 10 of 12, including the last three at San Francisco.
Former third baseman Ryan Zimmerman made a pair of diving catches in left field to highlight a stellar defensive effort, and Tanner Roark (5-4) allowed two runs and seven hits in six-plus innings to propel Washington to another victory.
"We're playing great as a team right row," said Roark, who struck out four and walked none. "Just keep it going. It's exciting."
Brandon Crawford and Pablo Sandoval each drove in a run for the Giants, who have lost a season-high tying three straight after winning five in a row.
Cain's struggles might have been the most disappointing thing of all for the Giants.
In his second start since a stint on the disabled list with a strained right hamstring, the former ace reverted back to his early season woes against Washington. Cain gave up four runs and three hits in five innings, walking five and striking out four.
"It was too much of a deficit to come back from. We needed a better start than that. I wanted some clean innings. I made it too difficult," Cain said.
The finale of the four-game series is Thursday, but the NL East-leading Nationals already have handed San Francisco its first series loss since the Giants were swept at Pittsburgh from May 5-7. Before the Nationals showed up in San Francisco this week, the Giants had not lost two in a row since May 16-17 to the Marlins.
The Nationals are doing it by getting contributions at the plate, on the mound and in the field.
After Crawford's RBI triple in the fourth, second baseman Danny Espinosa made a diving stop on Gregor Blanco's sharp grounder and threw out the speedy runner at first. Zimmerman, filling in for Harper in left, also swiped another run from San Francisco in the sixth when he made a diving catch of Crawford's slicing fly after Michael Morse doubled.
"I'm kind of learning on the fly," Zimmerman said. "Got a good break on it. It kept tailing away. I dove and caught it. The landing wasn't very smooth, but in the end, I caught the ball."
Sandoval, scratched from the starting lineup because of an illness, singled home a run as a pinch-hitter in the seventh to whittle Washington's lead to 4-2. Zimmerman slid in to snag Angel Pagan's short fly for the third out.
With his back right leg almost touching the dirt, Werth went low to launch his sixth homer of the season to put the Nationals up 4-1 in the fifth. Werth, who had not homered since May 14 at Arizona, singled with two outs in the ninth off Yusmeiro Petit to extend Washington's lead to 6-2.
Drew Storen, Tyler Clippard and Jerry Blevins each tossed a scoreless inning to help Washington finish off San Francisco again. Closer Rafael Soriano had been warming up in the bullpen before Werth's single.
"The best part about that is we could put the big scary guy back in his cage," Werth said, "and save him for [Thursday]."
The Nationals placed catcher Wilson Ramos on the 15-day disabled list with a strained right hamstring and called up catcher Sandy Leon from Triple-A Syracuse. ... The Giants traded left-hander David Huff back to the Yankees for cash. He was sent to San Francisco in January for cash after the Yankees signed Masahiro Tanaka. ... Tim Hudson (6-2, 1.97 ERA) takes the mound for the Giants opposite Washington's Blake Treinen (0-2, 1.78 ERA) in Thursday's series finale.