WASHINGTON — Daniel Murphy added to his stellar start, homering and driving in three runs to help John Maine and the Mets rout the Washington Nationals 12-0 last night.

Murphy went 3-for-6 and scored twice and is batting .467 (14-for-30) since being called up from Triple-A New Orleans on August 2. His RBI single drove in the first run of the eight-run third that gave New York a 10-0 lead.

That big inning made it an easy night for Maine (10-7), making his first start since July 28. Maine, on the 15-day disabled list with a mild right rotator cuff strain, allowed one hit in five innings. He struck out six and walked four.

The Mets sent 13 batters to the plate in the third and scored eight runs on just four hits off Washington starter Jason Bergmann (2-9), who walked five in a 51-pitch inning. The Nationals walked 11 overall in their sixth straight loss.

David Wright and Carlos Delgado both reached base twice in the inning. Wright walked and singled and scored twice while Delgado walked twice and scored once.

Carlos Beltran added a two-run double while Murphy and Fernando Tatis had RBI singles. Bergmann even walked John Maine with the bases loaded.

Maine walked a second time and reliever Brian Stokes got his second career hit as Mets pitchers reached base three times.

Stokes pitched the final four innings to complete the four-hitter.

Notes: Commissioner Bud Selig was in town for the owners meetings and came to the game. … Washington outfielder Ryan Langerhans left because of right side/lower back tightness after pinch-hitting in the fifth. … Washington’s Lastings Milledge extended his hitting streak to 15 games with a second-inning single.