WASHINGTON -- Ian Desmond scored three runs and had three hits, including a home run, and hot-hitting Adam LaRoche had two hits and scored twice as the Nationals beat the Cubs 7-3 on Friday in the opener of a three-game series.
Washington (20-15) won for the seventh time in eight games behind starter Ross Detwiler (2-3), who won for just the second time despite an ERA of 2.50 at game time. He went six and 2/3 innings and allowed eight hits and two earned runs.
The Cubs (13-22) had four leadoff doubles in the first seven innings but could not capitalize for starter Jeff Samardzija (1-5), who entered with an ERA of 3.09. Chicago has now lost six of its last eight games.
LaRoche has a seven-game hitting streak and has 11 hits in his last 23 at bats.
Desmond finally was retired on a groundout in his fourth at bat in the eighth off Chicago reliever Shawn Camp, a product of nearby George Mason University.
Starlin Castro and Ryan Sweeney had two hits for the Cubs.
Craig Stammen came on in the seventh for Detwiler and finished off the Cubs despite allowing a run in the ninth.
Washington took a 7-2 lead in the fifth on a two-run double by Danny Espinosa. His hit followed an RBI double by Desmond, whose third hit in three at bats scored Ryan Zimmerman to make the score 5-2.
Desmond hit a two-run homer in the fourth against Samardzija to give Washington a 4-2 lead. It was the 500th hit of Desmond's career.
Chicago tied the game at 2 in the third on an RBI double right by Castro. His hit scored starting pitcher Samardzija, who had doubled to left.
The Cubs could have taken the lead 3-2 but Washington right fielder Roger Bernadina threw out Castro at home on a single by Anthony Rizzo later in the third.
Washington took a 2-1 lead in the bottom of the second on a two-run double to right-center by Kurt Suzuki, whose hit scored Desmond and Espinosa.
The runs were unearned as Desmond reached on an infielder grounder then went to second as Espinosa reached on an error when Samardzija could not field a dribbler to the mound.
The Cubs took a 1-0 lead in the first as Castro, batting leadoff for the first time this year, doubled to right and scored on a groundout by Rizzo against Detwiler. Smardzija went five innings and allowed seven runs, five earned.
Outfielder Bryce Harper did not start for the Nationals due to an operation for an ingrown toenail on his right foot, according to manager Davey Johnson. "He was in a lot of pain last night," Johnson said before Friday's game.
Johnson said he expects Harper, 20, to miss just one game. He is hitting .302 with 10 homers.
NOTES: Before the game, the Cubs activated right-handed pitcher Kyuji Fujikawa off the 15-day disabled list while right-handed pitcher Rafael Dolis was sent to Triple-Iowa. "I am going to ease him in," Cubs' manager Dale Sveum said of Fujikawa, who had had been on the DL since April 13 with a muscular strain of his right forearm. Dolis has not allowed a run in two appearances with the Cubs this year. ... Right-fielder Jayson Werth, bothered by a sore hamstring, is headed to the DL. "He is not doing too good," Johnson said before the game. Werth was doing leg curls Friday when he had leg spasms, according to Johnson. If Werth has to go on the DL, Johnson said possible outfield replacements are Eury Perez and Jeff Kobernus, both of who are with Triple-A Syracuse. Perez is hitting .346. Perez was not in the starting lineup Friday night in Syracuse. ... Camp graduated from Robinson High in Fairfax, Va., about 20 miles south of Nationals Park. He said his father and sister will attend the weekend series. Camp entered the series with an ERA of 8.03. "Some of us (in the bullpen) need to be more consistent, myself included," he said. ... The teams were involved in a bench-clearing brawl Sept. 6, 2012 at Nationals Park.