Washington hit double digits in runs for the second straight night in Arizona in a 10-4 win Tuesday.
The Nationals (63-44) scored four in the fifth with homers on consecutive pitches by Wilson Ramos (.331/.381/.536, 16 HR, 59 RBI) and Chris Heisey (.223/.315/.436, 5 HR, 9 RBI) to break a 2-2 tie.
Daniel Murphy (.356/.395/.623, 20 HR, 79 RBI) was 2-for-5 with two RBI, and rookie second baseman Wilmer Difo had three hits, an RBI and a stolen base.
Rookie center fielder Trea Turner (.324/.360/.479, 0 HR, 10 RBI) was 2-for-5 with an RBI and two runs scored.
Tanner Roark (11-6, 3.02 ERA, 1.17 WHIP) was the beneficiary of the onslaught, getting the win after giving up three runs on seven hits in six and a third innings, striking out six and walking two on 103 pitches, 68 for strikes.
The Nats have a six-game lead on Miami (57-50) in the NL East.