Ian Stewart and Seth Smith hit three-run homers, Aaron Cook struggled through five innings for his 15th victory and the Colorado Rockies beat Washington 7-2 on Sunday, handing the Nationals their season-high 10th straight loss.

It's the longest skid for the Nationals since they moved to Washington before the 2005 season, and the franchise's worst since the Montreal Expos dropped 11 games in a row from June 23-July 4, 1991.

With 37 regular-season games remaining, the Nationals need to go 19-18 to avoid the club's first 100-loss campaign since the Expos went 55-107 in 1976.