Ian Desmond had a solo shot for the Nationals while starting pitcher John Lannan (2-2) earned his first victory in seven weeks, giving up only one earned run in seven innings.
Washington closer Matt Capps got out of a huge jam in the ninth inning to earn his major league-leading 17th save in 18 chances.
The Nationals protested the game due to an incorrect lineup card. Adam Russell was listed as San Diego's starting pitcher, but it was Clayton Richard who took the mound.
Richard (4-3) gave up two homers, compared with just one in his previous nine starts combined.
In Denver, Manny Ramirez broke out of a slump with a go-ahead two-run homer in the sixth inning as Los Angeles beat Colorado.
Ramirez capped the Dodgers' four-run sixth with his 549th career home run and first at Coors Field, clearing the center field wall to put the Dodgers on top by a run.
The drive was his first since April 18 and broke a tie with Mike Schmidt for 14th on the all-time list.
Jonathan Broxton got three outs for his 12th save, helping the Dodgers end the Rockies' season-high five-game winning streak.
A homer by Matt Kemp leading off the fifth ended Colorado's Jeff Francis' run of 16 1-3 consecutive scoreless innings. Francis (1-1) allowed five runs in 5 1-3 innings.
Los Angeles rookie Carlos Monasterios (2-0) took the win, giving up only two earned runs in five innings.
In Miami, Ryan Howard had two hits and scored Philadelphia's first run in 31 innings as the Phillies ended a dreadful slump by edging Florida.
Howard scored on a triple by Raul Ibanez, Chase Utley drove in the go-ahead run and Wilson Valdez had two hits for the Phillies, who had been shut out in each of their past three games — all against the New York Mets.
Jorge Cantu had two hits, and Chris Coghlan and Gaby Sanchez each scored for Florida, which dropped its third straight to fall under .500 (24-25).
Philadelphia starter Kyle Kendrick (3-2) made an errant throw to first that allowed Florida to score both of its runs but did not allow an earned run in six innings.
Jose Contreras allowed a pair of one-out singles in the ninth, before closing out his third save in three chances.
Florida starter Chris Volstad (3-6) gave up three runs in 6 1-3 innings.
In Chicago, Albert Pujols and Yadier Molina each drove in a pair of runs to help St. Louis down Chicago.
Cardinals starter Chris Carpenter (6-1) pitched into the seventh inning, allowing one run, striking out five and issuing just one walk.
Ryan Ludwick hit a two-run homer, and Colby Rasmus also drove in a run for St. Louis, who knocked Cubs starter Randy Wells (3-3) from the game after 16 pitches.
Wells allowed five runs without retiring a batter, and St.
Louis sent nine batters to the plate before the first out.
In Atlanta, David Ross and Chipper Jones each drove in three runs as surging Atlanta beat Pittsburgh.
The Braves had 13 hits, including three by Ross. Ross had a three-run double in the first and Jones knocked Pittsburgh's Zach Duke (3-5) out of the game with a two-run single in the sixth. Duke gave up seven runs in 5 1-3 innings.
Atlanta starter Derek Lowe (7-4) gave up only one run and one walk in seven innings. He improved to 9-0 in nine career starts against Pittsburgh.
In Cincinnati, Drew Sutton hit his first grand slam, joining one of the longest power surges in Cincinnati history, routing Houston.
Brandon Phillips and Jonny Gomes also connected off Astros starter Wandy Rodriguez (2-7), who gave up a season-worst eight runs in 3 1-3 innings.
The Reds have homered in 17 straight games, tied for the third-longest streak in club history.
Gomes also tripled home a run and singled in another.
Reds pitcher Sam LeCure went six innings to win his big-league debut.
Cincinnati is nine games over .500 for the first time in four years.
The Astros fell to 16-32 for the first time in franchise history. They had catcher Kevin Cash pitch the ninth to save a weary pitching staff.
In Milwaukee, Corey Hart ended the Mets' shutout streak at 35 innings with a game-winning two-out homer in the ninth, lifting Milwaukee over New York.
Mets starter Johan Santana pitched eight scoreless innings in a super performance, but the bullpen couldn't hold on for what would have been the team's fourth straight shutout.
Ryota Igarashi (0-1) gave up a single to Ryan Braun with one out in the ninth, and Hart homered with two outs for his first game-ending shot.
Brewers starter Yovani Gallardo (5-2) pitched his first career shutout, walking only one with seven strikeouts.
In San Francisco, Matt Cain pitched a one-hitter to match a career best as San Francisco sent Arizona to its fifth straight defeat.
Cain (3-4) gave up only a two-out double in the second. He struck out a season-high nine to end a three-start losing streak. He didn't walk a batter for the first time since his opening start of the year. This was his 10th career complete game and third shutout.
Pablo Sandoval hit a solo home run leading off the eighth, ending a 124 at-bat homerless drought. He also had a sacrifice fly and an RBI single, giving him a season-best three RBIs.
