WASHINGTON -- Ian Desmond isn't worried about the major league-leading 27 errors he's committed. His focus as his rookie season winds down is on an aggressive approach at the plate.
"When runners are in scoring position, it's time to just be aggressive," Desmond said. "Don't go down without a fight. ... Sometimes you don't get them in, but sometimes you do."
With the game tied at 3, Adam Kennedy led off the seventh with a single off Jordan Norberto (0-2). He advanced to second on pinch hitter Alberto Gonzalez's sacrifice bunt and, after Roger Bernadina popped out, Desmond singled to right for the lead.
"There's a lot of work to be done to be the player that I want to be," Desmond said. "I feel good. My first year, I'm able to help contribute with the offense, and my defense is what it is."
The hit broke a scoreless streak of 17 2/3 innings without an earned run by the Diamondbacks bullpen.
Coming off the shortest start of his brief career -- six runs in 4 1/3 innings against Florida on Tuesday -- Washington starter Stephen Strasburg departed after five innings with the game tied at 3. The right-hander's throwing error in the second led to two unearned runs in the Arizona second.
"You want to bounce back after a not-so-good outing before. But it's a new ballgame and I flushed all the stuff that happened before and I really wanted to go out there and do my thing," Strasburg said. "We were able to get a W today and that's what I want."
Strasburg allowed three runs -- one earned -- on five hits, walked none and struck out seven.
"Exactly what I expected," said Arizona second baseman Kelly Johnson. "We've seen enough film and TV and talked to enough people about him. It was exactly what I expected. It was fluid delivery. Nothing deceiving there. The ball jumps out of his hand. He's not afraid to come in."
Washington manager Jim Riggleman let Strasburg hit for himself in the fifth, then brought in Tyler Clippard in the sixth after a series of fans ran onto the field following Strasburg's groundout, causing a brief delay.
The protesters were urging Major League Baseball commissioner Bud Selig to move the 2011 All-Star Game from Phoenix because of Arizona's immigration legislation.
"Once we sat in there a little longer with the [protest] going on, I just decided, well I'm just not going to send him back out there," Washington manager Jim Riggleman said.
Adam LaRoche homered for Arizona, which finished its seven-game road trip 4-3.
"I'd like to be 7-0. I guess it's an improvement," said Arizona interim manager Kirk Gibson. "We had been terrible on the road. We're playing better."
Clippard (9-6) pitched two scoreless innings for the Nationals, who had lost six of seven. Drew Storen got the final three outs for his second save.
LaRoche led off the second by crushing a 2-0 fastball from Strasburg into the right-field stands for his 20th homer.
With one out, Mark Reynolds singled and later scored when Strasburg sailed a throw on Stephen Drew's dribbler over first base and into foul territory along the right-field line. Drew wound up at third on the error and Gerardo Parra's sacrifice fly plated him for a 3-0 lead.
"Instead of fielding with my glove, I barehanded it and then I realized after that I had a lot more time than I needed to," Strasburg said. "It pretty much just sailed on me. It was bad fundamentals all around for that play."
In the second, Willingham hit a leadoff double and scored on Ivan Rodriguez's one-out single to center. Willingham's two-run shot tied it in the fourth. Zimmerman singled to right before the homer, the first for Willingham in 33 games.
Arizona right-hander Barry Enright went five innings, yielding three runs on six hits. He walked one and struck out one.
Zimmerman made it 5-3 with a leadoff homer in the eighth off Esmerling Vasquez.
Riggleman is leaning toward having struggling RHP Jason Marquis make his next start. Since returning from the DL on Aug. 8, Marquis is 0-2 with a 7.00 ERA. ... Before the game, three dozen people demonstrated outside the ballpark, decrying Selig's insistence that the 2011 All-Star Game will remain in Phoenix despite controversy over Arizona's immigration legislation. In the bottom of the fifth inning, protesters ran onto the field, but a security guard snatched a banner pleading for a boycott of the game before it could be unfurled. While two protesters were being taken into custody, a banner reading "Bud Selig Move All Star Game No SB 1070" was displayed above the center-field batter's eye. ... LaRoche has six straight seasons of 20 or more homers. ... Enright has not given up more than three runs in any of his nine starts. ... Clippard's nine victories lead major league relievers. ... The attendance of 21,695 was the lowest attendance in Strasburg's seven home starts.