Rockies get to Storen again, top Nationals, 6-4
Storen (2-2, 2.70 ERA) was also the losing pitcher on Friday after giving up an eighth-inning grand slam to Carlos Gonzalez in a 5-4 loss.
Gonzalez went deep twice on Sunday, both times off Nats starter Max Scherzer, who gave up four runs on eight hits in six innings, striking out 10 and walking one.
Ryan Zimmerman also hit two homers, his eighth and ninth of the season, as part of a 3-for-4 day at the plate.
His other hit, a seventh-inning single, seemed poised to score Anthony Rendon from second with what would have been a tie-breaking run, but the throw from Gonzalez in right field beat Rendon to the plate.
Nationals manager Matt Williams challenged the out call, saying Michael McHenry was blocking the plate illegally, and though it appeared that Williams was correct on replay, the call was upheld.
Down two heading into the bottom of the ninth, Washington was able to load the bases with one out off Colorado reliever Tommy Kahnle, who struck out Jayson Werth and got Ian Desmond to ground out to short to end it.
Washington (57-53) remains a game and a half behind the New York Mets (59-52) in the National League East. The Mets lost to Tampa Bay on Sunday by a 4-3 final.