WASHINGTON -- Not even Arizona catcher Welington Castillo can figure out how he's the hottest hitter in a series involving star sluggers Paul Goldschmidt and Bryce Harper.
Castillo homered for the sixth time in eight games and the Diamondbacks seized upon reliever Aaron Barrett's throwing error on a bunt to surge past the Washington Nationals 11-4 Wednesday night.
"I don't know how to explain what's going on right now," said Castillo, who hit his second home run this series on a night that 15 of Arizona's 17 hits were singles. "Just go there, see the ball, hit the ball, just try to keep everything simple and not think about anything."
Arizona starter Rubby De La Rosa (9-5) only lasted five innings and struggled with command early, but was in line for the win when Washington turned to its bullpen in the sixth.
Sparked by the wild throw from Barrett (3-3) in the sixth that let two runs score, the Diamondbacks finished that inning leading 5-2. Castillo hit a three-run drive in the eighth and Arizona romped to its ninth win in 13 games.
Arizona also moved to 6-3 with one game remaining on a 10-game, bicoastal road trip.
Goldschmidt, Ender Inciarte and A.J. Pollock each got three hits.
"A lot of singles," Arizona manager Chip Hale said. "Sometimes that's our game, single them to death. I thought our guys extended at-bats and got hits at big times."
Castillo, now on his third team this season after stints with the Cubs and Mariners, is batting .393 (11 for 28) with two doubles and nine RBI in the eight games he's played on the road trip.
"Obviously it's great for us," Hale said. "A lot of guys get those pitches and foul them back. He's not doing that right now."
Castillo also helped guide De La Rosa through an uneven start that began with the Nationals taking a 2-0 lead on a pair of sacrifice flies from Ryan Zimmerman and Jayson Werth.
"We started to change our (pitches)," Castillo said of the approach with De La Rosa, who allowed just two hits three walks but threw 101 pitches over five innings. "Go soft, soft, soft and hard late."
Washington led 2-1 in the sixth when Arizona's Nick Ahmed tried to lay down a sacrifice bunt with runners at first and second and no outs. Barrett fielded the ball but threw it into foul territory.
Ahmed got all the way to third on the play, credited with an infield single, and then scored when pinch-hitter Jarrod Saltalamacchia followed with a broken-bat single. Aaron Hill later drew a bases-loaded walk to make it 5-2.
Six runs later, first baseman/outfielder Tyler Moore came on to pitch and got the last two outs for Washington.
Goldschmidt's three-hit night snapped him out of a mini-slump, having gone 0 for 15 in the past four games.
"There's so much failure in this game, so it's definitely more fun when you're having success," Goldschmidt said.
He was the first batter Moore faced and grounded out, although it drove in a run.
With the victory, the Diamondbacks moved to within two games of .500. Arizona has now posted identical 26-27 records at home and on the road.
Diamondbacks: Chief baseball officer Tony La Russa said RHP Chase Anderson (triceps inflammation) will come off the disabled list and start either Friday or Saturday.
Nationals: RHP Stephen Strasburg (left oblique strain) felt fine after throwing a bullpen session on Wednesday. Manager Matt Williams said they'll see how he feels Thursday before making some decisions. ... CF Denard Span (back tightness) hit and took fly balls in the outfield for the first time before the game. Span also felt fine and said he wants to wait and see how he's doing Thursday.
Arizona RHP Jeremy Hellickson (7-7, 4.95) has struck out 24 in his last 27 1/3 innings and will start in the series finale against Washington RHP Joe Ross (2-3, 3.00), a rookie who's never started vs. the Diamondbacks.
