Tyler Bozak scored the overtime winner and Auston Matthews had a goal and an assist as the Leafs pulled in front 2-1 in their series with Washington with a 4-3 win last night.
William Nylander and Nazem Kadri also scored for Toronto and Frederik Andersen made 23 saves.
The Leafs dug out from a pair of two-goal deficits in the victory, taking unlikely control of a meeting with the Presidents' Trophy winners.
Alex Ovechkin, Nicklas Backstrom and Evgeny Kuznetsov all scored in defeat for the Caps while Braden Holtby gave up four goals on 28 shots.
All three games so far have been decided in overtime.