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The impressive work by young roster candidates Brett Berard, Gabe Perreault and Brennan Othmann overshadowed the Rangers’ second straight third-period breakdown in Tuesday’s 5-4 preseason defeat to the Islanders at the Garden after holding a 4-2 lead at the intermission.

This was a different roster from Tuesday’s 5-4 OT defeat to the Devils in which the Blueshirts surrendered a 4-1 lead in the third.

This one might have rested more squarely on Hartford’s projected No. 1 netminder Dylan Garand, who surrendered a couple of wonky ones after replacing Jonathan Quick at the 40-minute mark.

“I think it happened two completely different ways,” head coach Mike Sullivan said. “But that’s not something we want to happen too often. We’ve just got to do a better job of controlling the momentum.”

Perreault got top-line work on the left with J.T. Miller and Mika Zibanejad, with Othmann stepping in for Artemi Panarin (lower body, day to day, skating on his own with coaches) on left wing to complete the Vincent Trocheck-Alexis Lafrenière connection.

Berard was on the left on the third, energy line with Noah Laba and Conor Sheary.

Berard went to the net to put away Laba’s backhand, through-the-legs centering feed at 7:33 of the second period to give his team a 3-2 lead at 17:33 of the second, 12 seconds after Othmann wired one from the left side on the power play with Matt Rempe providing traffic in front.

Perreault was on the puck throughout.

“We’re trying to see what we have and what guys are capable of,” Sullivan said. “I think they’ve shown glimpses of what they’re capable of and where their potential could be.

“That’s what preseason is all about, right? You put guys in situations and you see if certain players are capable of doing capable things. That’s what we’re trying to explore here.”

Sullivan called Perreault “a really exciting player for us.”

The coach said that Othmann “has shown glimpses of brilliance.”

The Rangers are still carrying 48 players. There should be a substantial cut ahead of Monday night’s game on Long Island.

“There are immediate decisions and big-picture decisions and we’re trying to balance the two,” Sullivan said. “We’re trying to find out what we have.”