Nationals 3, Mariners 1: Stephen Strasburg struck out eight in 7 2/3 innings and Jayson Werth hit a two-run homer as visiting Washington defeated Seattle for the second straight night.

Anthony Rendon added an RBI double for the Nationals, who increased their lead in the National League East to seven games over the Atlanta Braves. The Mariners lost for the fourth time in five games on their homestand and fell 1 1/2 games off the pace for the American League’s second wild card.

Strasburg (11-10) gave up one run and six hits and departed after allowing Dustin Ackley’s eighth-inning homer. Matt Thornton recorded the final out of the eighth and Rafael Soriano worked the ninth for his 30th save.

The Nationals clubbed a season-high six homers in Friday’s win over Seattle and were at it again in the first inning when Werth hit a two-run shot to left off Roenis Elias (9-12). Jose Lobaton singled in the fifth and scored on Rendon’s double to left-center field.

Kyle Seager and Endy Chavez had singles in the ninth before Soriano retried James Jones on a grounder to end it. Lobaton went 3-for-4 for the Nationals, while Austin Jackson and Jose Sucre had two hits apiece for Seattle.

GAME NOTEBOOK: Elias gave up three runs (two earned) and six hits in six innings. … Lobaton also had three hits in his last start Sunday against San Francisco. … Seattle OF Chris Denorfia (neck) was unavailable.