The New York Islanders blew a 4-2 lead in the third period on their way to a 5-4 overtime loss to the San Jose Sharks. Here's what Islanders head coach Lane Lambert said following the loss.

ELMONT, NY -- The New York Islanders seemed well on their way to a third-straight win on Tuesday. 

Three straight goals from Brock Nelson, Mike Reilly, and Ryan Pulock had the Islanders up 4-1 over the league-worst San Jose Sharks with just over eight minutes left.

However, New York once again couldn't seal the deal in the third. 

Kevin Labanc began a rally for the Sharks, with Tomas Hertl completing a hat trick with two goals with the goalie pulled. William Eklund beat Ilya Sorokin in overtime, capping off a 5-4 overtime loss for the Islanders.

Head coach Lane Lambert called it "completely unacceptable" to lose the game. "We had the game under control with eight-and-a-half minutes left. To lose that game is a sin."

For the Islanders, it's a continuation of a trend that began on Oct. 30 against the Detroit Red Wings. 

With New York up 2-0 in the third period, Detroit rallied for three goals in four minutes to take the lead. The Islanders did get the game to overtime, but Lucas Raymond finished the game in the extra session.

Later that week, the Islanders held a 3-0 lead against the division-rival Carolina Hurricanes. With a 3-1 lead entering the final frame, goals from Dmitry Orlov and Jesperi Kotkaniemi forced the game to overtime once again, with Sebastian Aho scoring the game-winner.

Following the Carolina loss, Lambert said, "We've given away a couple of multi-goal leads, certainly not a recipe for success. Is it a trend? No, it's too early, but certainly something we need to make sure doesn't become a trend."

Fast forward to December, and it certainly has.

Lambert attributed Tuesday's loss to poor decision-making in the big spot, something he's noticed in the team's blown leads. "It's on our stick, we turn it over, and it ends up in the back of our net," Lambert said.

On the fourth goal, he added, "We have a chance to make a play with it, shoot it down into the empty net. We turn it over, it ends up in the back of our net. So what happened was too many turnovers in those situations. We've got to do a better job of managing the puck, taking care of the puck, and getting the job done."

Since Oct. 30, New York has squandered 10 leads in the third period. 

Examples since that game include 3-2 leads lost against the Vancouver Canucks and Seattle Kraken, a pair of one-goal advantages lost to the Calgary Flames, and a two-goal edge against the New Jersey Devils prior to a regulation loss.

While New York did pull out a victory against Calgary, snapping a seven-game slide, as well two points in their rematch with the Hurricanes after blowing two leads, they've lost six of the eight games in which they've blown the game in the third. New York also blew a one-goal lead in the third period to the Buffalo Sabres in their season opener but overcame it to win 3-2 in regulation.

After tonight's game, Lambert added, "It's happened too many times. It just has to stop. That's it. Bottom line."

Matthew Page contributed to this report.