With one out and nobody on, manager Manny Acta took left-hander John Lannan out of the game in favor of right-hander Julian Tavarez. Kevin Youkilis came to the plate and hit a routine ground ball to Zimmerman, but his low throw bounced in front of first baseman Nick Johnson, allowing Youkilis to reach base safely.
"I just threw it away," Zimmerman said. "I had a good grip and everything. It was a bad throw. Obviously, it has been something I have been working on all year. I will continue to work on it. I have no excuses or anything. I just made a bad throw."
Boston then took advantage of the situation. Jason Bay singled to left fielder Adam Dunn, who grabbed the ball and made a fundamental mistake. Instead of throwing to second, Dunn threw to third base. Youkilis was safe at third and Bay advanced to second on the throw.
After Mike Lowell was walked intentionally, Jason Varitek hit a sacrifice fly to left to score the go-ahead run.
"It's a typical example of where we are at right now," Acta said. "We didn't play good defense. We allowed them to take the lead on poor defense. Some other stuff that doesn't come up on the box score: We didn't throw the ball to second base; we allowed the runner to get an extra base."
The bullpen then had problems getting hitters out. The Red Sox added to their lead by scoring six runs in the eighth inning. Jacoby Ellsbury highlighted the scoring with a two-run triple against Jesus Colome.
In the ninth inning, right-hander Joel Harahan allowed Dustin Pedroia to score on a Youkilis double.
After the game, Acta said he needed Colome, Hanrahan and Kip Wells to step up and pitch better. They allowed a combined five runs in two innings on Tuesday. Acta indicated that there could be changes to the bullpen soon.
"The other four guys [Joe Beimel, Mike MacDougal, Tavarez and Ron Villone] are the ones pitching the crunch-time innings. [The other guys] were supposed to go out there and keep us in the game and [they] can't do it. Then somebody else is going to come up here and do it."
The game seesawed in the first six innings. The Nationals were able to get right-hander Brad Penny in first inning as Dunn doubled to right field to drive in Zimmerman.
Lannan lasted 6 1/3 innings, giving up three runs on nine hits.
"He threw 109 pitches -- we have to take care of this kid," Acta said.
Said Lannan, "I wasn't as good as my last one [against the Yankees]. I was up in the zone a little more and relied on my changeup a lot more today. These guys are a great hitting team. I had to use my changeup as much as possible. When you fall behind this team, they really look for their one pitch. I made some pitches when I had to."
The Red Sox quickly tied the score in the top of second inning, when Bay hit his 19th home run of the season.
Boston and Washington both scored run in the fourth. In the top of the inning, Ellsbury tripled over the head of center fielder Willie Harris to score Bay and give Boston a 2-1 lead.
In the bottom of the inning, the Nationals had the bases loaded with Harris at the plate when Penny threw a wild pitch to score Zimmerman.
Later in the inning, Washington had the bases loaded with one out, but couldn't score any more runs. Anderson Hernandez hit into a force out and Lannan struck out to end the inning.
"We wasted a good opportunity there," Acta said. "Again, our situational hitting is not up to par. We had a chance there to take the lead and build some momentum. We just couldn't score a run."
In the fifth inning, Youkilis gave Boston a one-run lead with a single to left. By the sixth inning, however, the Nationals tied the score when Harris doubled down the right-field line to send Josh Bard home.
"It was a very good ballgame until the eighth, but, still, I knew in the seventh inning that we were not going to win, 3-2, because they already have four runs," Acta said. "You have to take advantage when you have the opportunity to score. We didn't, again."