For Donatas Kupsas, Long Island Lutheran’s 58-47 boys basketball win over visiting Iona Prep was frustrating.

Kupsas, a 6-8 sophomore forward, scored 15 points, grabbed seven rebounds and dished three assists. But he said he felt unsatisfied.

“Everybody wants to practice,” he said, “because we know that we played bad.”

The Crusaders (14-2) had trouble pulling away from an Iona Prep team missing its two best players, Virginia-bound Ty Jerome and sophomore Bryce Wills. Turnovers and periodically stagnant offense kept Lutheran from expanding an early 13-point lead and sent the Crusaders into halftime up 28-23.

At that point, Kupsas had reason to be frustrated. He had scored six points but also had been whistled for two fouls as his team struggled.

But after the break, it was a different story. Kupsas (nine points) and Indiana-bound Devonte Green (13) combined for 22 of the Crusaders’ 30 points. Kupsas battled underneath and corralled three of his five offensive rebounds in the third. His poise with the ball in the high post helped Lutheran break down Iona Prep’s 2-3 zone.

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“He does a lot of things you don’t have to coach,” coach John Buck said. “He has a really good feel for the game. The fact that he’s only a sophomore is amazing. He has certainly a ton of potential.”

Kupsas’ layup off Green’s assist with 5:01 left gave Lutheran a 53-33 lead, its largest of the game. With 2:15 left, Green caught a pass from Kupsas alone and in stride and finished a tomahawk dunk, the dagger that put the Crusaders ahead 57-39 and convinced Buck to empty his bench.

“He’s real consistent,” said Green, who finished with 20 points, five steals and four assists. “He’s going to be real good in the next couple of years. That’s my guy. I like playing with him.”