Phoenix, AZ (Sports Network) - Adam Dunn and Ivan Rodriguez each hit solo home runs for Washington, and Livan Hernandez pitched effectively into the eighth inning in a 3-1 victory over Arizona in the opener of a four-game set.
Hernandez (8-7), coming off his shortest stint of the season, allowed only five hits, one walk and one run to go with five strikeouts in 7 1/3 innings for the Nationals, who were coming off a 4-2 homestand.
Sean Burnett recorded the final five outs for his first save of the season.
Rodriguez's blast was the 300th of his career as a catcher, joining four other backstops to accomplish such a feat.
"It takes a lot from you [to hit 300 home runs as a catcher]. To be able to get it done is a nice feeling," said Rodriguez of the elite company he joined.
Rodrigo Lopez (5-10) took the loss in a quality start, yielding three runs on seven hits and two walks in seven frames for the Diamondbacks, who left all their offense in New York after taking two of three from the Mets by a 27-12 margin.
Justin Upton went 0-for-4, snapping a 17-game hitting streak in defeat.
Lopez got off to a slow start in the first inning, though he limited the damage to one run. The right-hander picked off Nyjer Morgan following his leadoff single then walked the next two batters.
Josh Willingham's two-out single plated Adam Kennedy for a 1-0 game, and Rodriguez blasted his second homer of the season leading off the next frame.
Mark Reynolds scored Arizona's only run in the bottom half on a Gerardo Parra groundout, and Dunn got the run right back for the visitors with his 26th round-tripper of the year in the third.
"Early in the game I was leaving the ball up and making pitches, and they took advantage," Lopez said.
Washington wasted runners on second and third with one out in the seventh, and Arizona failed to score with two on and one out in the eighth, as Burnett relieved Hernandez and fanned Kelly Johnson, then got Upton to chase a 3-0 pitch out of the zone for a weak groundout to short.
Burnett closed out the win in the ninth by retiring Arizona's 4-5-6 hitters in order.
This was the first meeting between the clubs this season...Hernandez, who pitched for Arizona during the 2006 and '07 seasons, lasted just 4 1/3 innings against the Braves last Wednesday, taking the loss in a 3-1 decision... Rodriguez joins Mike Piazza (396), Carlton Fisk (351), Johnny Bench (327) and Yogi Berra (306) in the elite 300-home run club for catchers...Stephen Drew had two of Arizona's five hits...Game time: 2:19.