Kyle Okposo and Blake Comeau tallied within 45 seconds of each other in the first period for the Isles, who had won two straight and four of five coming into the game. Joey MacDonald allowed three goals on 28 shots to take the loss.
After regulation ended in a 2-2 tie, the Leafs struck quickly in the extra period. After an Islanders turnover in their own zone, Anton Stralman blasted a slapshot that MacDonald saved. The shot brought the goaltender too far out of the net, and Grabovski's shot from in close easily found the net 50 seconds into the frame.
Stempniak's wrister from the slot put Toronto on the board with 2:33 left in the opening period, but Okposo tied the game 15 seconds later after jamming the puck past Gerber from right in front of the crease.
Comeau's wrister just 45 seconds after the previous goal staked the Isles to a 2-1 lead at the conclusion the first period.
After a scoreless second period, Toronto tied the game on Ponikarovsky's 19th goal of the year at the 8:46 mark of the third. Neither team could muster the game-winner down the stretch, sending the game to overtime.