SAN FRANCISCO -- Ian Desmond was looking to go deep in his last at-bat. He settled for a lopsided Washington win.
Desmond came to the plate in the ninth inning needing a home run for the cycle -- and he swung for the fences.
"You don't get that opportunity very often," he said. "For the record, I probably shouldn't have slammed the bat after I got out. I was caught up in the moment."
San Francisco had its five-game winning streak snapped.
Strasburg (6-4) allowed four hits over six innings and retired his final 10 hitters. He struck out seven and did not walk a batter, improving to 3-0 against the Giants with 29 strikeouts in 25 innings.
Nationals starters have struck out 52 and walked one in their last seven games.
Washington manager Matt Williams, who played 10 seasons with the Giants, said Strasburg was pulled as a precaution with some tightness in his back.
"He could have kept pitching," Williams said. "The third inning he started experiencing it. Once we tacked on a couple runs late, we decided to get him out and make sure he got some treatment."
Ryan Vogelsong (4-3) retired 10 of 11 batters during one stretch and pitched into the seventh. But he gave up six runs and nine hits, ending his three-game winning streak.
"I threw some really good pitches and I threw some really bad ones," Vogelsong said. "I just had a bad night, that's all."
Strasburg set down 13 of 14 batters after Crawford's RBI single.
"My changeup was working really well," Strasburg said. "It kept them off the fastball. I didn't need to use my curve that much. I was able to throw the change for strikes."
Desmond, who owns a .373 career batting average against the Giants, also has an impressive .434 mark (23 for 53) and 51 RBIs with the bases loaded.
"I just swing hard in case I hit it," he said. "The last few years the Giants have been at the top and I think I rise to play the best, but I don't really have an answer. I'm going to keep doing what I'm doing."
Desmond's two-run single with the sacks full in the third gave Washington a 4-1 lead. Desmond also tripled home a run in the second and added a two-run double in the seventh.
Werth drove in the Nationals' first run in the first inning and added an RBI single in the seventh. He also scored on an error.
The Giants scored their first run in the second. Tyler Colvin doubled with one out and came home on Crawford's single. Arias added an RBI single in the eighth.
Strasburg struck out the first batter he faced in four of his six innings. He also ended three innings with a strikeout.
"He has good stuff," Giants manager Bruce Bochy said. "He throws 95 (mph) with a good slider and change. His ball is moving and he was on top of his game."
Nationals INF Anthony Rendon (sore right hand) was out of the starting lineup for a third straight game. He's expected to start Tuesday. ... Giants OF Angel Pagan was out of the lineup with a bruised right shin. ... Giants RHP Santiago Casilla is expected to start a rehab assignment at Class-A San Jose on Wednesday or Thursday. ... RHP Doug Fister (4-1, 3.19 ERA) pitches Tuesday for the Nationals. He's walked two batters in 36 2/3 innings this year. LHP Madison Bumgarner (8-3, 2.86) starts for the Giants. He's on a six-game winning streak.