Maple Leafs\' Alexei Ponikarovsky, rear, and Nik Antropov (80) celebrate a goal against the Capitals. (AP Photo/Manuel Balce Ceneta)
Toronto led 2-1 before Bryan McCabe scored at 10:09 of the second period with the Maple Leafs enjoying a two-man advantage. Jeff O'Neill scored another power-play goal 14 seconds later, and Hal Gill concluded the rapid-fire barrage against Capitals goaltender Brent Johnson at 11:09.
Darcy Tucker added his team-high 16th goal just over three minutes later for a 6-1 lead.
Andrew Raycroft had 22 saves for the Maple Leafs, who went ahead for good on a goal by Kyle Wellwood at 1:03 of the first period.
Alex Ovechkin scored a power-play goal for the Capitals, who have lost five straight.
Washington played without left wing Donald Brashear and centre Brian Sutherby, both of whom were serving NHL-mandated suspensions stemming from Wednesday's melee against Atlanta. In addition, Alexander Semin sat out a third straight game with an upper body injury.
Toronto got off to a torrid start, scoring on its second and fifth shots to lead 2-0 at 2:44 of the first period. After Wellwood got his fifth goal with a blast from between the circles, Michael Peca beat Johnson on a breakaway after gaining possession of the puck in the Capitals' end.
Washington peppered Raycroft with several good shots before Ovechkin finally broke through with a goal late in the period. It was his 14th goal of the season and sixth in five career games against Toronto.
The second period was dominated by the Maple Leafs, who scored on four of nine shots. With two Capitals in the penalty box, McCabe extended his career-high scoring streak to eight games with a wrister from the top of the right circle.
Seconds later, Johnson attempted to retrieve the puck behind the net and returned to the goal too late to stop a shot by O'Neill. Gill made it 5-1 with a blast from just inside the blue line.
Tucker scored off a pass from O'Neill, who intercepted a poor clearing pass by Washington's Shaone Morrisonn, and Matt Stajan put Toronto up 7-1 with a power-play goal in the third period.
Notes: Toronto captain Mats Sundin, who has been out since Nov. 6 with a torn elbow ligament, could return Saturday against Boston. ... For the first time this season, the Capitals have lost two straight in regulation. They fell 4-2 to Atlanta on Wednesday. ... McCabe has four goals and eight assists during his eight-game run.