In the two clubs' four meetings this season, the Nationals have lit up Giants pitching for a combined 38 runs, winning all four games.
Monday saw the biggest explosion so far with Washington putting up a season-high 14 runs in a runaway victory.
The Giants will attempt to change their fortunes against the team with the best record in baseball when they meet again Tuesday for the second game in the three-game series.
Trying to keep the Nationals' high-powered offense in check for San Francisco will be lefty Madison Bumgarner. Looking for his 13th win of the season, the 23-year-old was a tough-luck loser his last time out against the Cardinals when he tossed six strong innings, giving up just three hits and three runs in the 3-1 loss.
The majority of the damage came on a Carlos Beltran two-run homer off Bumgarner.
"That was pretty much what I wanted to throw there. I didn't think he'd keep it fair, but he did," Bumgarner said after the game. "I felt good for the exception of really just one pitch that really hurt me. That was pretty much it."
Opposing Bumgarner for the Nationals will be Cy Young candidate Jordan Zimmermann. The 26-year-old made perhaps his most dominant start of the season Thursday against the Astros, tying a career high with 11 strikeouts and giving up three hits in six shutout innings. He's allowed one or zero earned runs in 14 of his 23 starts this year.
"I feel like I have a pretty good season going right now," Zimmermann said. "I just want to finish strong and not fall off toward the end, and I guess whatever awards are out there, hopefully I get mentioned in some of them, but the main goal right now is to make the playoffs."
What has made the righty so dominant, according to his catcher, has been his willingness to go directly after hitters and not dabble around.
"He attacks the zone," Nationals catcher Kurt Suzuki said. "He runs that fastball up there, mid-upper 90s. It's impressive. The impressive part is he goes right at you. He ain't trying to trick you. He ain't trying to nibble. Here it is, hit it. That's the kind of mentality you need."
Nationals: Werth scratched
Jayson Werth was a late scratch from the lineup in Monday's series opener against the Giants.
The Nationals announced about 45 minutes before the game that Werth, who was slated to bat sixth and play right field, wouldn't start due to right ankle soreness.
Werth has been dealing with general soreness, particularly in his legs, since returning from the disabled list Aug. 2. The outfielder left a game in Houston on Aug. 6 due to leg soreness, but he was back in the starting lineup Wednesday after manager Davey Johnson kept him out of the starting lineup for precautionary reasons Tuesday.
The Nationals are 9-0 in games Werth has started since coming back from the disabled list.
Giants: Sandoval to play Tuesday
The Giants activated Pablo Sandoval from the disabled list before Monday's series opener against the Nationals, optioning Brett Pill to Triple-A Fresno to make room on the roster for the two-time All Star.
Although he was not in the lineup Monday, manager Bruce Bochy said he expects Sandoval to be back in the lineup for the next two games against the Nationals. He fouled out as a pinch-hitter in the ninth inning of Monday's game.
"I wasn't going to start him all three games," Bochy said. "He says he feels great. The day off will be good. He should be 100 percent at that point."
Sandoval finished a three-game rehab assignment with Class A San Jose over the weekend. After straining his left hamstring on July 24 while playing first base against the Padres, Sandoval said he still isn't running at full speed.
"I don't want to push it right now," Sandoval said. "But every day, I feel better and better."
The Giants have 23 come-from-behind wins this season. Only four have come after the seventh inning.
By winning Monday, the Nationals reached 28 games above .500. The 1933 Nationals were the last team in franchise history, while in Washington, to climb as many as 28 games above .500.