Nationals 4, Dodgers 1: Ross Detwiler pitched six strong innings and host Washington clinched its first postseason berth in 31 years.

Ryan Zimmerman and Danny Espinosa delivered run-scoring doubles and Drew Storen struck out the side in the ninth for his third save as the Nationals clinched at least a wild card spot while extending their lead in the National League East to 5 1/2 games over the Atlanta Braves.

Detwiler (10-6) allowed just one run and three hits as he stymied Los Angeles, which lost for the 10th time in 14 games to slip three games behind the St. Louis Cardinals for the NL’s second wild card spot.

Zimmerman had a run-scoring double in the third and scored later in the inning on a wild pitch. Mark Ellis homered in the fourth for Los Angeles, but Washington tallied twice in the bottom of the frame on Espinosa’s double and Kurt Suzuki’s sacrifice fly.

Dodgers starter Chris Capuano (11-11) allowed four runs (three earned) and six hits in five innings while losing for the sixth time in his last seven decisions.

GAME NOTEBOOK: Washington stole three bases – two by OF Jayson Werth (2-for-3 with a walk) and one by SS Ian Desmond (also 2-for-3 with a walk). … Dodgers reliever Kenley Jansen (irregular heartbeat) pitched for the first time since Aug. 27 and retired the only batter he faced. … The Nationals were originally formed as the Montreal Expos in 1969 and made the playoffs just once in 36 seasons in Canada.