Rangers coach David Quinn assured his confidence in goaltender Alexandar Georgiev prior to giving him full rein of the net in the preseason finale.

And the 23-year-old netminder made his best case to be Henrik Lundqvist’s backup with his performance in the Rangers’ 4-2 loss to the Islanders in Bridgeport, Conn., on Saturday night.

With 22 saves in his first full 60 minutes between the pipes this preseason, Georgiev looked in midseason form. The Islanders dressed the same team that will likely face the Capitals on opening night next week, while the Rangers kept core players Artemi Panarin, Brady Skjei and Mika Zibanjed off the ice.

But Georgiev looked poised against the likes of Anders Lee and Mathew Barzal, while keeping the Rangers — who dedicated Saturday’s matchup to evaluating “bubble players” ahead of their upcoming roster decisions — in the game despite the ballooning score.

“I felt confident,” Georgiev told The Post following the loss. “Everybody played a really good defensive game, and I didn’t think too much about [who was on the ice for the Islanders].”

A few minutes into the first period, Georgiev was dialed in, robbing an aggressive Lee at the crease. He maintained his vision on long shots during the Islanders’ two power plays in the opening frame and throughout the remainder of the game — which saw the Rangers take six penalties — consistently coming up big on the penalty kill.

The Rangers were called for three penalties in the second period, two of which came after Vladislav Namestnikov netted the first goal of the game. Georgiev was tested shortly after taking the lead, as the Isles came down hard on the next rush. But the goalie stood tall on a power-play look from Barzal to Lee, whose backhanded shot was swallowed up by Georgiev. He followed with a right-pad save on a hard shot from Johnny Boychuk from the blue line.

Michael Dal Colle knotted the game at one following a power-play goal off an odd-man rush as time expired in the second period.

Namestnikov was called for interference in the third, which allowed Josh Bailey to take the lead after finding position for an easy one-timer. Tony DeAngelo tied it for the Rangers just under a minute later before Georgiev outlasted two more penalty kills. And he escaped an Islanders ambush in the crease in the final six minutes that ended in a scuffle behind the Rangers’ net.

Georgiev even finessed a tough pad-save on Bailey with under five minutes to go, but Barzal buried the game-winner before Adam Pelech registered an empty-netter to put the game out of reach.

“I thought he made some big saves when he had to,” Quinn said of the undrafted goaltender. “[He] didn’t have a lot of work early, but in the third period I thought they came at us a little bit, had us on our heels a little bit, but I thought he did a good job fending them off.”

It’s telling that Quinn decided to give Georgiev a full game with Igor Shesterkin available to split the work, which the Rangers have done for the majority of the preseason. The two are still vying for a spot behind Lundqvist on the final roster, and though Shesterkin — who the Rangers took at 118th overall in 2014 — has been expected to assume that role when he’s ready, Georgiev has only impressed in his opportunities under Quinn.

“I think our whole team played really great, everybody put their top effort on the line trying to make a good impression in the last game,” Georgiev said. “It’s been a very fun game and unfortunate that it ended with a loss, but everybody battled hard and as long as we do that, I think we’ll be in a good spot to get wins [in the future.]”