The Islanders may have another chance to break out the brooms.

After putting together the strong start they’ve been looking for all series, the Islanders continued to finish like they have all postseason, this time carrying their tenacious late-game play into overtime to beat the Washington Capitals 2-1 on Sunday afternoon at Scotiabank Arena in Toronto and secure a 3-0 lead in their first-round series.

Taking a feed from Jordan Eberle, first-line center Mathew Barzal crashed the Capitals net and cut through the crease to backhand the puck in at 4:28 of overtime for his second goal of the postseason. The goal immediately went under review for offsides but ultimately counted as the winner.

“It was tight, I knew it was tight,” Barzal said of the game-winning play on a Zoom call. “I run that play a little bit in practice, or even in games, just try to sneak behind the D a little bit and just time it perfectly on the blue line. Great heads up play from Ebs, just great touch on the pass. I’ve had that play a few times this year and I’ve looked five-hole or short-side, decided to take this one far post and it paid off.”

The Islanders, who couldn’t close out the Panthers on the first try in the qualifying round, will take a swing at the sweep in Game 4 at 8 p.m. Tuesday.

Coach Barry Trotz had been looking for the Islanders to open games as strongly as they’ve been finishing them, which they accomplished after jumping to a 1-0 lead and outshooting the Capitals 14-6 in the first period.

However, overtime was a test the Islanders had yet to face in the Toronto bubble — a test they passed with flying colors.

“I liked our start, I thought in the second and third we got loose in some areas,” Trotz said. “We can clean that up, those are things you can clean up in our game. You knew that the team on the other side was going to come hard and they’re loaded, they got lots of weapons, they can do a lot of different things.

“We just stayed with it. … We know we’ve got another level in our game, which is really good to know.”

Islanders goaltender Semyon Varlamov, who came up with back-to-back saves on Capitals forward Jakub Vrana just before Barzal’s winner, turned aside 22 of the 23 shots he faced.

The Islanders commanded the first period and instantly put the Capitals, who were without Nicklas Backstrom for the second straight game, on their heels.

Later in the first, Washington goaltender Braden Holtby was forced to make a big stop on Brock Nelson, who then hit the post right after. After a strong shift from the Isles, Anders Lee called for the puck to receive a pass from Adam Pelech for the tap-in at 14:50 of the first.

Just over five minutes into the second, Eberle was called for slashing and sent the Islanders on their first penalty kill of the day. Evgeny Kuznetsov capitalized with a snipe from the right circle to knot the game at one at 5:50 of the second.

A scoreless third period forced overtime, in which the Islanders escaped a couple dangerous chances from Washington before Barzal finished things off.

“For one, there’s no tougher game than a game to clinch a series,” Lee said. “It’s going to be no different in Game 4 here. It’s going to be a tough game and we played a good one tonight and were able to come out on top, we still got a lot of work to do to make this thing right.”