UNIONDALE, N.Y. - Just before their fifth game in eight nights, the Toronto Maple Leafs finally got a break.

Not one that gave them any extra rest but provided them a chance to fire away at an emergency goalie making his NHL debut.

Tomas Kaberle scored the first of Toronto's three third-period goals to break a tie against surprise Islanders starter Mikko Koskinen as the Maple Leafs beat New York 5-3 on Tuesday night for their fourth win in five games.

Toronto is 12th in the East, eight points behind eighth-place Carolina with 28 games remaining.

"You can see we're sniffing a little closer and closer," said Colby Armstrong, who had a goal and two third-period assists. "We just have to worry about ourselves and get our points and get our wins when we can.

"We need to put some games together big time to give ourselves a chance."

New York was forced to start Koskinen after backup goalie Kevin Poulin injured his left knee during the warmup, minutes before the opening faceoff. Poulin left Nassau Coliseum on crutches and will have an MRI on Wednesday.

Armstrong and Jay Rosehill gave Toronto a 2-0 lead on the Maple Leafs' first two shots at the 22-year-old Koskinen, who was 5-15 in the AHL.

While the Maple Leafs' mindset was to keep putting pucks on the net, they had only eight shots midway through the game.

"It was a bit of a doughnut game. We weren't very good in the middle," Toronto coach Ron Wilson said. "With the quick start, we thought it was going to be easy especially with the kid they had in goal.

"He has been struggling in the American League and it showed early."

Nikolai Kulemin stretched it to 4-2 with 11:11 left and Fredrik Sjostrom made it a three-goal lead with 5:07 remaining. James Reimer made 31 saves for Toronto, which won on the road for the first time since Jan. 11 to break a five-game skid.

Toronto had plenty of jump in its legs one night after beating Atlanta 5-4. Kulemin also scored in the third period Monday.

Matt Moulson and Michael Grabner scored to pull the Islanders even, and Rob Schremp added one with 1:52 left, but it wasn't enough. Koskinen and Poulin are up from the AHL only because No. 1 goalie Rick DiPietro is injured and Dwayne Roloson was traded to Tampa Bay earlier this season.

Koskinen made 21 saves.

Poulin fell awkwardly in the crease after he caught his left skate in a rut, and was helped to the dressing room.

"There wasn't much time to do anything. I didn't even have time to be nervous," Koskinen said. "I can't be happy with the third period.

"I made a couple of mistakes that cost the win."

New York recalled Joel Martin from Bridgeport of the AHL, and the 28-year-old goalie was dressed and on the bench in the third.

Koskinen and the Islanders seemed to be in store for a long night as the Maple Leafs scored on the first two shots the six-foot-five Koskinen faced.

Armstrong beat the hulking Finn 1:29 in with a shot from the middle of right circle. Rosehill made it 2-0 only 5:02 later as Koskinen could hardly be faulted for that one as Rosehill deftly got his stick on the puck in the slot to deflect in defenceman Luke Schenn's drive for his second career NHL goal.

"I felt bad for him, not expecting to play and then getting thrown in there and the first two shots go in," Reimer said. "They weren't bad goals by any means.

"There is nothing much the kid could do."

Moulson started the Islanders' comeback with his team-leading 19th goal, that was set up by a brilliant pass from John Tavares with 9:12 left in the first.

Koskinen got a chance to show off his skills a bit in the second, first denying Clarke MacArthur's quick shot in-close during a 2-on-1 break -- a save that left him with splattered snow on his left shoulder -- and then doing the splits to make a lunging glove grab of Armstrong's drive.

Grabner, who was stopped on a short-handed breakaway in the second, tied it 2-2 with 4:58 left in the period.

NOTES -- Toronto C Darryl Boyce had three assists. ... Rosehill scored his other NHL goal Oct. 10, 2009, against Pittsburgh. ... Armstrong has 13 career assists against the Islanders, his highest total for an opponent. ... The Islanders had won three straight and nine of 12 against Toronto. ... After earning his first NHL shutout Thursday, Reimer was pulled Saturday after allowing five goals on 30 shots in two periods of a 6-2 loss at Buffalo.