Halak set the team mark with his 33rd win of the season, and Ryan Strome and Cal Clutterbuck provided just enough offence to lift New York to a 2-1 victory over the Flames on Friday night.
With the Islanders protecting a 1-0 lead in the final seconds, Halak cleared the puck down the ice but it was stopped well before it got close to the empty Flames net. Soon after New York doubled its advantage, Josh Jooris ruined the shutout bid and made it a tense one-goal affair again.
"I'm not happy about it, but we got the goal and we won 2-1," Halak said. "They don't give up. They play until the last second. I was glad when it was over.
"I wanted to have a shutout. I wasn't thinking about a goal, but I didn't get either of them. I got a win, so that's a good thing, right?"
That put the Islanders two points ahead of the rival New York Rangers, who drew even with them atop the Metropolitan Division on Thursday.
"We just focused on trying to win," Islanders captain John Tavares said. "We obviously see the standings. We know we're jockeying for positioning."
Halak stopped 26 shots, beaten only by Jooris with 20.9 seconds left. The Islanders had made it 2-0 with 41.3 seconds remaining on Cal Clutterbuck's empty-net goal.
It was fitting because Clutterbuck had a goal waved off 4:25 into the third period when the officials ruled that Brock Nelson had interfered with Flames goalie Karri Ramo in the crease.
"It happens," Tavares said. "We fought hard for that, but we stuck with it. It was good to see Clutter get rewarded at the end."
Ramo stopped 37 shots for the Flames, who without injured captain and leading scorer Mark Giordano missed a chance to move into a wild-card position in the Western Conference playoff race. Ramo's only blemish was Strome's early goal, the first power-play tally Calgary has allowed in exactly a month.
"We didn't give them much," Ramo said. "We played good, we battled. Just wasn't enough.
"Guys were playing more minutes and stepping up without Gio. We tried hard."
Calgary dropped to 1-2 on its seven-game road trip. The Flames lost 1-0 to the Rangers on Tuesday.
The Islanders took a 1-0 lead in a most unusual way, scoring the first power-play goal against the Flames in 14 games.
Tavares was stopped by Ramo, but the puck came back out front to Strome in the slot for his 14th goal. Calgary had gone a team-record 13 games without allowing a man-advantage goal. The streak of penalty-kills was snapped at 26, dating to Jan. 27 against Buffalo.
Strome has five goals in eight games.
"You go to the dirty areas and just kind of bang away. We'll take them any way we can get them," Strome said. "We talked about how they haven't really given up many goals, never mind the power play.
"It wasn't the prettiest goal, but we'll take it."
New York had the better of the play in the opening period and held a 15-7 edge in shots, but one of Calgary's attempts was Michael Ferland's failed penalty shot after he was impeded on a breakaway by defenceman Johnny Boychuk with 6:20 left.
Both teams had brief flurries in the second. Calgary got back to its strong penalty killing and held the Islanders' power play in check during its second advantage of the first period and the only one they had in the second frame.
New York, which held an 11-8 edge in shots in the middle period, began the third short-handed. The Islanders killed the penalty despite pressure by the Flames on Halak just before Lubomir Visnovsky left the box.
"They have one of the fastest team in the league," Flames coach Bob Hartley said. "The pace was real quick and it was tough to generate."
The task became more difficult without the defenceman Giordano, who skated in pregame warmups after being injured Wednesday in a 3-1 win at New Jersey.
"Gio is our captain and a warrior," Hartley said. "When Mark says he can't play, that says a lot. He really wanted to, but couldn't."
NOTES: Halak had shared the win record with Billy Smith, Chris Osgood, and Rick DiPietro. ... Ferland has no goals in 13 career NHL games. ... The Islanders will finish a four-game homestand Saturday vs. Carolina before a four-game trip.