The NHL's leading scorer with 33 goals and 72 points in 68 games, Tavares drove hard to the net and sneaked his way through a crowd of Maple Leafs defenders before beating goaltender Jonathan Bernier (39 saves) for the game-winner.
Tyler Kennedy, Frans Nielsen and Casey Cizikas scored for the Islanders (43-21-4), who scored three goals in the third period and rallied from a 3-1 deficit to force overtime. Michal Neuvirth made 22 saves for his first win with the Islanders after being acquired from the Buffalo Sabres at the NHL Trade Deadline.
Tavares, who grew up in neighboring Oakville, Ont., said scoring in Toronto is extra special.
"Yeah, it was great," said Tavares, who has nine goals and 12 assists in his past 13 games. "I had a lot of friends and family here. When I get the opportunity to get one, especially in overtime, it's a good feeling. It's nice to come through."
Tavares said with time running out in overtime, he simply reacted to what was in front of him.
"I just tried to gain some speed," Tavares said. "I saw the defenseman reacting, he backed off and I was able to hesitate enough to open up Bernier. I was happy it trickled in because I didn't get a whole lot on the shot."
Tavares said the ability to come back is a very good sign for a team that hopes to experience a long run in the Stanley Cup Playoffs.
"I think we know we didn't play our best in the first couple of periods but we got some life on our first goal," Tavares said. "Then a power-play goal got us back in the game with a lot of time left. We just tried to put them on their heels and we skated better as the game went on."
The Islanders are atop the Metropolitan Division and coach Jack Capuano feels his captain deserves serious consideration for the Hart Trophy as the NHL's most valuable player.
"No. 91 leads out team and his game-winner was a great individual effort," Capuano said. "If you look at our team nobody gave us a chance to be in the playoffs, so now that we're winning people seem to talk a little about us. He's our captain and he's having a tremendous year. At the beginning of the year, the numbers were not there for him. He's been on a good run and hopefully that will continue. He leads by example and he has been real good of late."
The Maple Leafs (26-35-6) took a 1-0 lead at 18:23 of the first period on a fine individual play by right wing David Booth. The speedy veteran muscled his way past Nick Leddy and Ryan Strome, cut to the net and beat Neuvirth with a hard backhand shot to the top corner on the far side of the goal. It was Booth's fourth goal of the season and third in as many games.
Kennedy, playing in his first game for the Islanders since being acquired from the San Jose Sharks at the trade deadline, put his new team on the board at 1:32 of the third period when he accepted a pass from Tavares and connected on a wrist shot to the short side from a sharp angle. It was Kennedy's fifth goal of the season.
James van Riemsdyk restored Toronto's two-goal lead five minutes later when he broke into the New York zone on the left side and snapped a 30-foot shot past Neuvirth for his 23rd goal of the season. It was his second goal in 18 games.
"I think there were some good things and you have to try to take away the positives when we have a lot of guys out of the lineup," Maple Leafs coach Peter Horachek said. "But when you have a 3-1 lead, that's the part that stings a little bit. You fought for it and you want to finish the right way."
Nielsen made it 3-2 at 9:58 with a tap-in from the side of the net 29 seconds after Booth was penalized for holding. Thirty seconds later, Cizikas tied it when he redirected Travis Hamonic's shot past Bernier for his seventh goal of the season.
"We were flat a little bit to start the game for whatever reason," Capuano said. "We broke down structurally on a couple of faceoffs, but we were resilient and found a way to come back against a good team, a team that is hungry, and win the game."