Adam LaRoche's tie-breaking, two-run home run in the sixth inning helped lift the Washington Nationals to a 4-2 win over the San Francisco Giants in the opener of a three-game set at Nationals Park.
LaRoche ended 2-for-4 and Ian Desmond had three hits and scored two runs for Washington, which has won four straight.
"I can't remember the last time when we put four wins together," said LaRoche. "It feels like it hasn't happened this year. We just have to build off of it and see where it takes us."
Joaquin Arias went 4-for-5 with two runs scored for the Giants, who have lost two straight and seven of their last 10.
"I have no complaints with his game because he did everything he could do," said Giants manager Bruce Bochy about Arias. "We need more people to step up and we need them to do it now."
With the game tied 1-1 in the sixth, LaRoche blasted his decisive homer into the seats in right. Desmond, who led off the inning with a single, scored ahead of LaRoche for the two-run cushion, 3-1.
Guillermo Moscoso (1-1) surrendered the blast and as a result suffered the loss. The reliever was charged with the two runs on two hits, with two walks and two strikeouts in two innings.
The Giants did get a run back in the seventh when Hunter Pence singled home Arias, but Washington countered in the eighth when Kurt Suzuki's sacrifice fly scored Jayson Werth.
Tanner Roark (2-0) got the win, tossing two innings of relief. He was charged with one unearned run on three hits.
Rafael Soriano worked the ninth for his 30th save of the season.
In a matchup that featured the two winningest left-handers the last two seasons on the hill, Mother Nature spoiled the fun. A one-hour, 17-minute rain delay prior to the start of the fifth inning forced both starters, Washington's Gio Gonzalez and San Francisco's Madison Bumgarner, from the game.
Gonzalez, who has 28 wins combined in the last two seasons, yielded just four hits, walked two and struck out a pair. He was nursing a back tightness all night.
Bumgarner, who has 27 wins in that span, was touched for one run on five hits, walking one and striking out four in four innings. He allowed his one run just prior to the delay, when Desmond scored from third after Wilson Ramos' grounder up the middle ricocheted off the hurler's leg and to Pablo Sandoval at third for the 1-5-3 ground out.
The Giants, though, got him off the hook when play resumed. With runners on the corners and two outs, Buster Posey's grounder up the middle went under the glove of Desmond at short for an error, allowing the tying run to score.
Giants first baseman Brandon Belt extended his hitting streak to eight-games, finishing 1-for-4 ... Posey's fourth-inning single ended an 0-for-13 slump for the SF catcher ... Ramos was pulled from the game after the delay because of an apparent hamstring injury ... Gonzalez remains winless since July 10 ... Washington starters have allowed just 16 earned runs in 61 1/3 innings this month ... Bumgarner has yielded just 15 earned runs in 75 innings over his last 11 starts ... Washington improved to 4-3 on a nine-game homestand ... This was the start of a six-game road trip for the Giants ... LaRoche has 17 HRs this season.