NEW YORK -- The St. Louis Blues are unbeaten through three games, but they know they'll have to finish better in order to turn the good start into something sustainable.

Vladimir Tarasenko scored twice in the second period and converted in the shootout Monday afternoon as St. Louis survived a furious third-period comeback by the New York Islanders to earn a 3-2 win at Barclays Center.

"It's good to get a win," Tarasenko said. "But we can't play like this in the third period and just let a team score on us and tie the game."

For most of the matinee, it appeared as if the Blues would cruise to victory behind Tarasenko's goals and a 5-for-5 performance by the penalty kill.

St. Louis survived 83 seconds of a 5-on-3 opportunity shortly before Tarasenko's first goal, a nifty tally in which he managed to shed the Islanders' Jordan Eberle by doing a 180-degree turn and firing a backhanded shot past Thomas Greiss at the 9:38 mark.

"It's hard not to just sit there and be in awe," Blues head coach Mike Yeo said of Tarasenko. "He's so powerful, and the way he held off (Eberle) and was able to spin around and make the play -- pretty impressive."

The Blues took advantage of a power play to double their lead with 4:26 left in the second when Tarasenko, stationed in the middle of the right faceoff circle, maneuvered a shot around a kneeling Calvin De Haan and past Greiss.

But the Islanders peppered Blues goalie Jake Allen with 16 shots in the third period and forced overtime on goals by Andrew Ladd with 6:56 remaining and Anders Lee with 59.2 seconds left.

The Blues (3-0-0), who were also perfect through three games last year, have been outscored 6-2 in the third period this season. St. Louis also carried a shutout into the third period of Saturday's 4-2 win over the Dallas Stars and blew a two-goal lead in the final seven minutes of regulation in a 5-4 overtime win over the Pittsburgh Penguins last Wednesday.

"It's one breakdown and next thing you know, we weren't executing," Yeo said. "When the score's tied or earlier in the game (when) both teams are pushing, I think that's when we play our best hockey. We've got to make sure we continue to do that for 60 minutes."

The Blues controlled the play in the overtime, though they couldn't take advantage of a power play late in the five-minute session when Islanders defenseman Nick Leddy was whistled for slashing.

But St. Louis wasted no time in the shootout, when Brayden Schenn and Tarasenko scored on the first two shots while Allen turned back both Islanders attempts.

"We're finding ways to win," said Allen, who recorded 40 saves in regulation and overtime. "We've got to be able to capitalize a little bit more and close out some games, but we're moving in the right direction."

The Islanders (1-1-1) have lost two of their first three games for the second straight season.

"Wasn't out best game there," Islanders center and captain John Tavares said "Not easy to come back in this league, especially in the third period. Tough to really do a whole lot. We battled through it and got a point, almost had two."

Greiss made 33 saves in regulation and overtime.

"It's a big point, being down 2-0 against that hockey club," Islanders head coach Doug Weight said, "Home or road, we'll take the point. We would love to get two, but I'm not too greedy."

NOTES: The Blues improved to 8-1-0 on Columbus Day while the Islanders fell to 6-8-1-1 (wins-losses-overtime losses-ties). ... The Islanders scratched RW Cal Clutterbuck (lower body) as well as D Ryan Pulock and D Dennis Seidenberg. ... The Blues scratched D Nate Prosser, C Oskar Sundqvist and RW Chris Thorburn. ... Blues rookie C Tage Thompson played 10:34 in his third career game. Thompson's father, Brent, is a former NHL player who currently coaches Bridgeport, the Islanders' affiliate in the American Hockey League.