Tony Cruz drove in two runs for the Cardinals, who have won nine of the last 10 games between the teams.
St. Louis took control with a three-run second inning fueled by third baseman Anthony Rendon's throwing error, capped by Lynn's first career extra-base hit. The Nationals, in their first season under former Gold Glove third baseman Matt Williams, are averaging more than an error per game and lead the majors in miscues.
Lynn (4-0) gave up one run and five hits over 5 2-3 innings in becoming the NL's first four-game winner. After the right-hander lost his control in the sixth, Kevin Siegrist retired Danny Espinosa on a two-out fly ball with the bases loaded.
Trevor Rosenthal worked the ninth for his fifth save, but not without difficulty. Washington put runners on second and third with one out, and Kevin Frandsen drove in a run with a groundout before Rosenthal struck out Jayson Werth on three pitches.
Espinosa homered for the Nationals, but he was the only player to get past first base against Lynn until the sixth.
Zimmermann (1-1) allowed four runs, only one of them earned, in seven innings. He struck out six and walked two.
Although Zimmermann came into the game 0-3 with an 8.27 ERA in six career games against the Cardinals, Williams insisted that would have no bearing on this appearance.
"I don't know if we make too much of it," Williams said before the game.
Zimmermann took the loss but probably deserved a better fate. The right-hander has beaten every NL team except St. Louis and Pittsburgh (one start).
St. Louis bolted in front for good in the second inning.
After Rendon threw wide on a potential force play at second, Cruz sliced a two-out, two-run single to right field and scored on a double by Lynn. It was the pitcher's first extra-base hit in 115 career at-bats and his fourth RBI.
The tainted inning extended a series trend that began Thursday night, when the Nationals made three errors, and continued Friday when Washington scored two unearned runs in a 3-1 win.
Espinosa led off the fifth with his first home run since last May 5.
In the Washington sixth, Werth singled and Adam LaRoche walked before Rendon looked at a third strike after getting ahead in the count 3-0. Lynn then walked Ian Desmond on four pitches before Siegrist retired Espinosa.
Matt Holliday delivered a two-out RBI single for St. Louis in the seventh, and successive doubles by LaRoche and Rendon got Washington to 4-2 in the eighth.
NOTES: Washington left fielder Bryce Harper exited after six innings. There was no explanation given by the Nationals. ... The game drew a sellout crowd of 41,084. ... The Nationals activated OF Denard Span from the 7-day disabled list and optioned OF Steve Souza Jr. to Triple-A Syracuse. Span started in the leadoff spot and got two hits. ... Stephen Strasburg (1-2) starts for Washington in the series finale Sunday against RHP Shelby Miller (1-2), who went 2-0 against the Nationals last year. ... Cardinals manager Mike Matheny remains undecided on his starter Monday against the Mets, although he suspects it will likely involve a roster move. The spot became vacant when RHP Joe Kelly strained his left hamstring Wednesday and went on the DL.
Link to box score: St. Louis (11-7) 4 at Washington 3
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