Staal, Erik Cole, Frantisek Kaberle and Tim Gleason all had two assists while Cam Ward was beaten once on 26 shots for the Hurricanes, whose five power-play goals equaled a franchise record for a single game.
The Southeast Division-leading Hurricanes rose to a four-point advantage over the idle Capitals. The two teams meet in Washington Tuesday.
Atlanta's lone goal was scored by Jim Slater. His seventh goal this season was scored shorthanded at 16:53 of the second.
Goalie Johan Hedberg was beaten seven times on 35 shots for the Thrashers, who have lost five of their last six games.