The Nationals were able to grab the lead in the first inning thanks to a fielding mistake.
With Denard Span on base after a single, Scott Hairston's grounder to DJ LeMahieu was mishandled on a force attempt. The throwing error allowed Span to score all the way from first and the Nationals led 1-0.
But in the bottom of the first, the Rockies teed off on Stephen Strasburg. Josh Rutledge and Corey Dickerson connected on back-to-back doubles and it was 1-1. Ben Paulsen added a run-scoring single to give Colorado the lead. A Michael McKenry single brought home Nolan Arenado, who had walked, and the Rockies lead was 3-1.
Update: The Nationals scratched out a run in the fifth. Danny Espinosa doubled and then stole third. Span brought him home with an RBI single and the Rockies lead is down to 3-2.
Update II: The Rockies added a run in the sixth. Charlie Blackmon with a RBI single to make 4-2. Strasburg finished 5 1/3 innings, allowing nine hits, four runs, all earned, three walks and struck out five. He threw 100 pitches and 63 for strikes.
Update III: Colorado extended its lead with two more runs in the seventh.
Arenado drove in the first with an RBI double off reliever Aaron Barrett and scored a batter later after a series of mistakes.
Arenado moved up to third on a wild pitch and then scored when Paulsen struck out, but reached on a missed catch error by first baseman Adam LaRoche.
The Rockies now lead 6-2 in the eighth.
Update IV: Despite four hits from Span and a two-run rally in the ninth, the Nats never recovered from the Rockies' three-run first, falling 6-4 at Coors Field.
Jayson Werth and Anthony Rendon provided back-to-back RBI singles off LaTroy Hawkins with two outs in the ninth. LaRoche then reached on an error to load the bases, but Ian Desmond struck out to end the game.
That snapped the Nats' winning streak at four and dropped their record to 55-44. Washington remains 1 1/2 games ahead of Atlanta in the National League East, but that could be down to a game should the Braves beat the Marlins tonight.
Strasburg suffered his second straight loss to slip to 7-8 on the season. He has now allowed eight runs in 12 1/3 innings (5.84 ERA) over his last two starts.
Lefty Jorge De La Rosa held the Nats to two runs (one earned) on eight hits in 7 1/3 innings to earn the win and avoid the sweep.