Adam LaRoche hit a two-run home run in the sixth inning to help lift the Washington Nationals to a 4-2 win over the San Francisco Giants on Tuesday.
The Nationals won their fourth game in a row on a night when neither starting pitcher returned after a thunderstorm caused a 1:17 rain delay.
Washington starter Gio Gonzalez threw four shutout innings. Giants ace Madison Bumgarner allowed just one run on an infield ground out in his four innings before the rain hit.
LaRoche sent a 1-0 pitch from San Francisco reliever Guillermo Moscoso (1-1) off the facing of the second deck above the Nationals bullpen in right field. That came after a leadoff single by Ian Desmond and broke a 1-1 tie.
Tanner Roark (2-0) earned the win with two innings of relief after the delay. Rafael Soriano got his 30th save of the season.
The Giants had evened the score after the rain delay ended because of a Desmond error at shortstop with runners at first and third in the fifth.
San Francisco scratched second baseman Marco Scutaro (stiff back), who was originally in the lineup. Joaquin Arias replaced him and had three singles and a double for a career-high four hits.
Even with the winning streak, frustrations have mounted for the Nationals in recent days. Earlier in the 11-game homestand, outfielder Bryce Harper and manager Davey Johnson argued in the dugout late in an Aug. 7 loss to Atlanta.
In the first inning on Tuesday, Gonzalez was late covering first base on a fielders' choice ground out.
After the inning, television cameras caught Washington outfielder Jayson Werth and Gonzalez in a verbal altercation in the dugout. Gonzalez had to be screened by pitching coach Steve McCatty as Werth walked away.
Meanwhile, the Nationals kept pressure on Bumgarner early. Washington stranded Anthony Rendon at second base in the bottom of the first after a one-out double. In the third, Bumgarner struck out Werth with a 92 mph fastball with the bases loaded and two out.
That good fortune didn't last. Desmond began the fourth with a double to right-center field. LaRoche followed with a single to right. Then Wilson Ramos hit a ball off Bumgarner's right knee. It deflected to third baseman Pablo Sandoval, who threw out Ramos as Desmond scored to put the Nationals up 1-0.
Gonzalez escaped a first-and-third jam in the first.
But he botched a bunt attempt in the second after a leadoff single by Scott Hairston. And he appeared to struggle with a sore back, stretching in the dugout between innings and consulting with McCatty and Washington trainer Lee Kuntz.
Gonzalez remained in the game, and kept San Francisco off the board. The Giants had runners at first and second in the fourth before Gonzalez struck out Brandon Crawford looking to end the threat.
That was the end of his night at 69 pitches. Thunderstorms moved in and halted the game at 8:28 p.m.
Kurt Suzuki added a run for Washington with a sacrifice fly in the eighth.
NOTES: Harper didn't start the game because he had the flu, according to Johnson, but made a pinch-hitting appearance in the eighth inning. . San Francisco CF Angel Pagan, on the DL since May 28 following surgery on his left hamstring, could start a rehab assignment at the end of this week, manager Bruce Bochy said. ... Nationals RHP Ross Ohlendorf, on the DL with a right arm injury, was expected to throw a bullpen session Tuesday and will make a rehab start on Aug. 15 or 16, according to Johnson. ... Washington LHP Ross Detwiler, on the DL since July 4 with a herniated disc in his back, won't resume baseball activities for at least another week, but is expected to return this season, Nationals GM Mike Rizzo said. ... San Francisco starts RHP Tim Lincecum (6-11, 4.18) on Wednesday in the second of a three-game series. He faces Washington RHP Jordan Zimmermann (13-6, 3.06).