Detwiler found himself in trouble in the first inning. With one out and nobody on, Alcides Escobar hit a ground ball that went past third baseman Willie Harris for an error. Harris was filling in for Ryan Zimmerman, who had the day off.
After Ryan Braun made the second out, it went downhill for Detwiler. The Brewers ended up scoring two runs, with Jonathan Lucroy highlighting the scoring with an RBI single to right.
Detwiler ended up throwing 44 pitches in that inning. The Nationals were thinking about taking Detwiler out of the game in the first, but he managed to get Joe Inglett to fly out with the bases loaded for the last out of the frame.
"The error ended up costing Detwiler some pitches, but Det has to find a way to pitch around that," manager Jim Riggleman said. "It's just one baserunner. We have to turn that into fewer than 40-something pitches.
In the fourth inning, an error by shortstop Ian Desmond proved to be costly. It came with two outs and a runner on second base. Dave Bush hit a ground ball to Desmond and it looked like it was going to be the third out of the inning, but Desmond threw the ball past Adam Dunn and that allowed Lucroy to score. Rickie Weeks followed with a homer over the left-field wall to give Milwaukee a 5-0 lead.
"We did not have a good day defensively today," Riggleman said. "Going into the series before the All-Star break and up to the current time, we played better defense. But we certainly didn't get it done today. We didn't make it easy for Detwiler. We made him throw a lot more pitches."
Desmond has made a Major League-leading 23 errors for the season. Riggleman continues to say that he has not lost his patience with Desmond.
"He is going to be here this year and 10 more after that. So we have growing pains with him," Riggleman said.
Harris, who felt he shouldn't have been charged with an error in the first inning, said the team has to find a way to improve its glovework.
During Spring Training, there was an emphasis on defense. The team got off to a good start during the first month of the season, but it's turned south after that.
"We have to play a lot cleaner baseball. It's ridiculous," Harris said. "We have to catch the ball and throw the ball. We have to take the pressure off our pitchers. We need to do a better job."
Bush was cruising through the first five innings, but the Nationals would make it a game by the seventh. Bush pitched six innings, plus one batter in the seventh, and allowed three runs on six hits.
"I thought his changeup was pretty much his pitch today," Brewers manager Ken Macha said.
It helped that Bush was able to have success with the changeup in the first inning.
"[Lucroy] called a couple in the first inning and I got a couple swings and misses on it," Bush said. "I had a decent feel for it today. It's not always a pitch I throw that much, but he figured out pretty early on that I had a good feel for it and called it a little more than usual and got some good outs out of it."
In the sixth, Josh Willingham had a sacrifice fly, while Dunn had an RBI single. An inning later, Adam Kennedy scored on an infield single by Nyjer Morgan.
"We had some good at-bats," Riggleman said. "There was a period in the middle of the game where the shadows made it impossible to see, but before and after that, I thought we had some pretty good at-bats."
But Milwaukee put it away in the seventh inning when Casey McGehee hit a three-run homer off Joel Peralta.
With the loss, the Nationals went 3-7 on the road trip. They hope to regroup and start winning at Nationals Park on Tuesday night against the Braves.
"I'm ready to get home and get some heat," Harris said. "This road trip has been horrific for us. Not taking anything away from the Brewers, but I think we are a better ballclub. Their numbers say that they are better. I'm with my guys. I think we are a better ballclub than what we have shown. We have to keep pushing, keep working."