The referee has yet to retrieve the ball and already the two teams cluster around him. They stare each other down with bent knees and furrowed brows, ready to pounce.

Yet for all their competitive spirit, these boys usually play, not against each other, but together.

Sophomore Alejandro Brown estimates that during the winter, at least 18 other boys on the varsity soccer team play futsal, a five-a-side soccer game on a basketball court-sized space, with the Massachusetts Futsal Association’s 5v5 League. The league pits friends against friends and teammates against teammates, fostering intense competition.

“You don’t want to lose to your friends,” said senior Tommy Kim. “If you lose to some other random team, you don’t see that random team at school, but if you lose to your friends, they talk about it the week after that.”

According to Kim, players begin trading barbs the week before a game.

“We’ll talk trash in school, like, ‘We’re gonna kill you, we’re gonna beat you,’ ” said sophomore Jacob Rosenkalt.

Yet for all the trash talk, senior Seb Dobrow said he feels that futsal strengthens the bond between teammates.

“It keeps the team chemistry together because we’re playing with each other for more than one season. By team chemistry, I mean that we all just love playing soccer together. Being the team that we are is what makes it the most fun,” said Dobrow.

“By the end of outdoor season, we’re always talking about how excited we are for futsal and what team’s going to beat the other team. Kids who maybe didn’t get as much time playing outdoors can play all the time indoors and still be a part of it.”

Hard feelings rarely remain come outdoor season, says Dobrow, because teams enter the game knowing that they share the same goal: winning.

“That’s the good thing about playing with friends, it never escalates to the point where it’s like Newton North versus Brookline, where you literally hate the other team,” said Kim. “It’s more like friendly competition that’s really intense because they’re your friends, too, so there’s no point in starting grudges.”

Brown believes the transition from rivals to teammates builds trust.

“Say I lost and my friend won. We’re already friends, but he’s accepting that I lost, and I’m accepting that he won,” said Brown. “We’re putting that behind us, so that’s already creating a level of trust, and now we’re onto the next thing, which is winning the next game.”

He added that, rather than creating lasting rivalries, competing against teammates has taught him greater respect.

“I’ve played them. They’ve beat me. Once I see, ‘Oh, these guys are good players,’ I have to respect them as players,” said Brown. “You respect them as players, and you learn how to deal with them. It’s all about growing in the soccer system and growing skill-wise as a person, too.”

Emma Nash can be contacted at [email protected].