A pair of wild pitches scored the tying run and the winning run for the Rockies, who won the rubber match of a three-game set against the Nationals, 4-3.
"I feel awfully good about the way we gutted that win out today," Rockies manager Jim Tracy said. "We got a couple breaks with a couple balls that went to the backstop, but we did, offensively, some good things to put ourselves in a position to get that."
Jeremy Guthrie tossed his second straight strong outing for the Rockies, despite receiving a no-decision. He gave up two runs on six hits and a walk in six innings.
Eric Young Jr. lined his second career home run to bring Colorado within a run and started the Rockies' rally in the eighth inning.
"I hit it and I was like 'aww, yeah,'" Young said. "That's one of those [batting practice] feelings when you know you catch one in [batting practice] and it was just a matter of if it had the height, and then once I saw it, it was like, 'yeah, that's gonna get over.'"
Nationals starter Jordan Zimmermann allowed a run on only three hits and two walks while striking out two. The 26-year-old right-hander retired 15 of the last 16 hitters he faced before being pinch hit for in the seventh inning with 95 pitches.
"I feel real bad on that one for [Zimmermann]," Nationals manager Davey Johnson said. "His record's not indicative of what kind of first half he's had. He's been outstanding."
The Rockies exploded when Zimmermann was replaced by Sean Burnett. Down 3-1 at the time, Young greeted Burnett by lacing a slider over the left-field fence. Dexter Fowler and Marco Scutaro followed with a pair of singles to put runners on the corners. Michael Gonzalez came on for Burnett, but his wild pitch allowed Fowler to score and tie the game. He struck out the next three hitters to escape the jam.
Colorado went back to work in the ninth against Tyler Clippard (2-3). Jordan Pacheco lined a double to the left-field corner to open the frame and advanced to third on a sacrifice bunt. Clippard then threw a wild pitch to score Pacheco and give Colorado the lead.
"You don't want to ever get too comfortable or too confident out there," Clippard said. "So this is a little check for ourselves. We can kind of regroup and move forward with a new beginning in the second half."
The Rockies got on the board first, taking a 1-0 lead in the second inning. Tyler Colvin singled, Todd Helton walked and Pacheco singled to load the bases with no outs. Wil Nieves then lofted a fly ball to left field to score the run.
Washington took the lead in the fourth inning when Ian Desmond launched a 3-2 slider over the center-field fence. The homer scored Adam LaRoche, who led off the frame with a double.
Pinch-hitter Roger Bernadina helped put another run across for the Nationals in the seventh when he reached on a two-out bunt single. He stole second and came around to score when Steve Lombardozzi grounded a single through the right side.
Rex Brothers (4-2) picked up the win after tossing a scoreless eighth and Rafael Betancourt notched his 15th save, despite allowing two men to reach base.
Fowler, who went 2-for-3, had multiple hits for the fourth straight game...Guthrie is 2-1 with a 2.41 earned run average in his career against the Nationals (15 earned runs in 56 innings)...Desmond leads major league shortstops with 17 home runs...The Nationals finish the first half with their second-best first-half winning percentage since moving to Washington (.590, 49-34). The team went 52-36 before the break in 2005...Zimmermann is 3-0 with a 1.80 ERA against the Rockies in his career...Zimmermann has worked at least six innings in all 17 starts this season...The Rockies head into the break 33-52...Colorado went 1-for-9 with runners in scoring position and left five on base...Washington went 2-for-7 with runners in scoring position and stranded seven.