SAN FRANCISCO -- Sweating, sniffling and sneezing, Pablo Sandoval felt horrible until his final swing.
Sandoval hit a towering two-run home run in the bottom of the 10th inning after Gregor Blanco's tying triple in the ninth, and the San Francisco Giants rallied past the Washington Nationals 4-2 on Tuesday night.
"You have to give 100 percent no matter what. It's your job to fight," said Sandoval, who was so dehydrated he had to receive intravenous fluids before the game.
Saddled with flu-like symptoms all week, Sandoval flipped his bat and shifted into a slow trot as soon as he sent the changeup off Yunesky Maya (0-1) over the right-center field wall for his eighth homer this season. It was Sandoval's second career game-ending hit -- both home runs against the Nationals -- and San Francisco's sixth walk-off win this year.
The ball landed just shy of the plaque on the brick wall marking Barry Bonds' record-breaking 756th home run.
"I don't think Bonds ever hit one that high," said Matt Cain, who allowed two runs in seven innings.
Blanco finished 3 for 4, including the RBI triple off closer Rafael Soriano with two outs in the ninth. The Giants' comeback upstaged a superb outing by Stephen Strasburg. Both starters lasted seven innings in a matchup of NL aces.
Jeremy Affelft (1-0) tossed a scoreless inning for the win.
Maya had been called up from Triple-A Syracuse earlier in the day after the Nationals placed reliever Ryan Mattheus on the 15-day disabled list. Mattheus broke his right pitching hand punching a locker following a loss at San Diego on Sunday.
"I don't feel good because I didn't make a zero and (keep) the game tied," Maya said.
Washington's fourth consecutive loss might be its most painful.
Buster Posey hit an infield single leading off the ninth against Soriano and was lifted for pinch-runner Andres Torres. With San Francisco down to its last strike, Blanco sent an 84 mph slider over the head of right fielder Bryce Harper for the tying triple.
Harper said he was thinking about the play last week when he ran face-first into the wall in a scary collision against the Dodgers and needed 11 stitches in his chin. He also missed two games because of a bruised left knee before coming back Monday night.
"I should have caught it. I put that whole loss on me," Harper said.
The Giants earned their 13th comeback win this season. After entering the game just 2-17 when trailing after the eighth inning, they handed Soriano his second straight blown save and third in 15 chances this year.
"We love pressure. It's our favorite part," Sandoval said.
What started out as a scintillating matchup on the mound faded at the finish.
Strasburg struck out seven and allowed five hits and three walks. Cain gave up four hits and two walks while striking out seven.
Strasburg had his changeup confusing hitters most of the night. He retired 14 of the final 15 batters -- six on strikeouts -- and never allowed a runner past first in his last five innings.
Ian Desmond and Ryan Zimmerman each hit an RBI double in the first to give the Nationals a 2-0 lead. Blanco singled, took second on Cain's sacrifice and hustled home on Angel Pagan's single in the second for San Francisco's only run off Strasburg.
Cain worked out of a bases-loaded jam in the fourth. He got Kurt Suzuki to ground into a fielder's choice and Strasburg struck out swinging after an appeal to first base umpire Gary Darling.
Neither starter faced a serious threat the rest of the way.
Marco Scutaro extended his hitting streak to 19 games -- the longest in the majors this season -- when he doubled off the left-field wall against Tyler Clippard with two outs in the eighth. Sandoval followed with a weak grounder to second to end the inning, then atoned for the out his next time up.
Sandoval's other game-ending hit came at Washington on May 12, 2009.
"He didn't show any effects from the bug there," Giants manager Bruce Bochy said. "He's got better discipline (at the plate) now. He's got more patience."
Several Nationals players wore a T-shirt in the clubhouse that had a younger image of pitching coach Steve McCatty shirtless from when he posed for Playgirl magazine's July 1984 issue after the photo recently surfaced on the Internet. The back of the shirt had the slogan: "Untuck." "I could have done without that revelation," manager Davey Johnson joked. "I didn't know he had that good a body, and I didn't know he had that much hair." ... Bochy said Johnson will be on his coaching staff for the NL All-Star team. "He's all set to go. I have tremendous respect for Davey," Bochy said. ... Madison Bumgarner (4-2, 3.09 ERA) will start for the Giants opposite Washington's Gio Gonzalez (3-2, 4.01 ERA) in a matchup of hard-throwing young lefties in Wednesday's series finale.