Bryan Little and Todd White each added a goal and an assist for the Thrashers, who rebounded from a seven-goal loss to Washington in their previous game. The loss to the Capitals was Atlanta's 10th in 11 games.
The injury-riddled Senators, who dropped their fifth straight, got their only goal from Peter Regin. Ottawa stars Daniel Alfredsson, Jason Spezza and Milan Michalek were all out with injuries.
The Senators have been outscored 22-5 during in the five losses.
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