Ross Detwiler fired seven innings of four-hit, shutout ball, Alam LaRoche hit a solo home run, and Ryan Zimmerman added a run-scoring double as the Nationals beat the Cubs in the first of a four-game series, 2-1.

Detwiler (9-6) allowed three walks and fanned three in his 93-pitch outing before getting help from Drew Storen (hold) and Tyler Clippard (30th save), who allowed a run in the ninth inning, but with a runner on second base, he fanned Josh Vitters for the final out with his trademark changeup.

Ian Desmond and Danny Espinosa had a pair of singles each. They also helped the Nats turn two inning-ending double plays, closing the sixth and seventh innings.

Washington (82-52) will hold its 6 ½ game lead over Atlanta (75-59), which appears on its way to a victory over Colorado, leading 6-1 in the eighth inning.