Ryan Zimmerman's line drive to right-center kept going — and going and going — until it landed in the first row, highlighting another big Fourth of July for the resurgent third baseman as the NL East-leading Washington Nationals beat the San Francisco Giants 9-4 Wednesday.

Zimmerman missed another home run by inches — he had to settle for an RBI double — on a humid day when the ball carried well at Nationals Park. He is 10 for 20 with four homers and 13 RBIs in six Independence Day games.

Undeterred by an 11:08 a.m. holiday start time that followed a late-finishing game, Washington rallied from an early deficit to move 15 games above .500, matching its season-high.

Edwin Jackson (5-4) settled down after a three-run first and allowed four runs and five hits in 5 1-3 innings. Three relievers combined to shut down the Giants the rest of the way.

Madison Bumgarner (10-5) followed last week's one-hit shutout of the Cincinnati Reds with one of his rockiest outings. He was done after five-plus innings and gave up three home runs, matching a career high. He allowed seven runs total, more than in his previous four starts combined.

Washington has scored 18 runs in the first two games of the series and will go for the sweep Thursday. The Giants have lost four of five — and have allowed nine-plus runs in consecutive games for the first time since 2009.

Zimmerman is batting .386 (17 for 44) since receiving a cortisone shot in his sore right shoulder on June 24. He was in a 5-for-49 slump at the time, and the travails of the team's No. 3 hitter were becoming a concern in a mostly positive first-half of the season.

Zimmerman drilled a line drive his first time up — but it turned into an out after Bumgarner made a nice slide in the grass to retrieve the ball after it hit the pitcher in the leg.

No one got in the way of Zimmerman his next two times up. His double that peppered the left field wall was part of a three-run third, and he and Michael Morse hit back-to-back opposite-field homers in a three-run fifth.

Rookie Jhonatan Solano joined in the offense in the fourth inning, hitting a liner similar to Zimmerman's. It initially looked like a gapper but carried into the seats for his second career homer in his ninth major league game. Rick Ankiel added a two-run, fly-ball homer in the eighth.

Nationals starter Jackson has a tendency to struggle in the first inning, and Wednesday was no exception. He walked Gregor Blanco to start the game and soon was behind 3-0 after Pablo Sandoval put a belt-high fastball over the center field wall.

NOTES: The Giants trickled into their clubhouse around 9 a.m., their body clocks on West Coast time and their bodies still weary from the rain-delayed game the night before. "We'll get some caffeine in us, some Red Bull, some coffee, something like that and push through it," Giants SS Brandon Crawford said. At least the early start left plenty of time to celebrate the holiday in the nation's capital, which held its traditional fireworks display on the Mall. "Yeah, get the rest of the night off," Crawford said. "You get to spend July 4 with the guys. So it will be fun." ... The Nationals returned C Sandy Leon from rehab, reinstated him from the 15-day disabled list and optioned him to Double-A Harrisburg. ... Matt Cain starts for the Giants in Thursday's series finale, facing Ross Detwiler of the Nationals.