WASHINGTON -- Daniel Murphy homered twice and drove in a career-high five runs and Jenrry Mejia pitched seven innings in his season debut as the Mets defeated the Nationals 11-0 Friday in the opener of a day-night doubleheader.
Murphy went 4 for 5, added a pair of RBI singles and tied his career high for RBI. He connected off Nationals starter Jordan Zimmermann (12-6) for a solo shot in the first and added a two-run homer in the third.
Juan Lagares had three hits and Ike Davis added a three-run homer for New York, which has won five of seven.
Mejia (1-0), who had been on the disabled since March with shoulder inflammation, allowed seven hits. He struck out seven with no walks.
Steve Lombardozzi and Ryan Zimmerman had two hits apiece for Washington, which was held scoreless a day after its dramatic 9-7 walk-off win over Pittsburgh.
Zimmermann, who surrendered seven runs in a career-low two innings Sunday in a 9-2 loss to the Dodgers, needed 118 pitches to go 6 2/3 innings. He allowed five earned runs on six hits while striking out eight and walking three in picking up his third straight loss.
With one out in the first, Murphy hit 1-1 slider off the second deck facade in right center to make it 1-0.
In the third, after Lagares doubled with two outs, Murphy put New York up 3-0 when he lined a pitch into the Nationals bullpen for his eighth homer.
New York added two in the seventh. Lagares singled home Anthony Recker, stole second and scored on a single by Murphy.
The Mets made it a rout with a six-run ninth capped by Davis' homer off reliever Drew Storen.
Murphy has hit safely in 15 of his last 16 games, going 26-71 (.366).
Mejia, 23, underwent Tommy John surgery in 2011 and spent most of 2012 at Triple-A Buffalo. He was 1-2 with a 6.33 ERA in three September starts for the Mets.
Prior to being recalled for Friday's start, the right-hander went 2-0 in a pair of rehab starts at Double-A Binghamton.
The Nationals had base runners in each of the first four innings against Mejia, but went 0 for 4 with runners in scoring position.
- After Washington OF Bryce Harper singled in the eighth, he was removed for pinch runner Scott Hairston.
- LF Eric Young Jr. was scratched from the Mets lineup after a pregame workout to test his right knee. He injured the knee Wednesday on the play in which Tim Hudson fractured his right ankle and left Thursday's game against Atlanta in the fourth inning.
- It was Murphy's second career multi-homer game. His first was June 27, 2012 against the Cubs.
- Zimmermann's eight strikeouts gave him 500 for his career.
- Washington activated RHP Ryan Mattheus from the disabled list. The reliever missed 58 games with a fractured right hand.