Syosset girls basketball is anything but child’s play.

The 21-3 North Shore squad is establishing itself as a dominant force this season, especially after their recent victory over Brentwood with a score of 54-46. This win not only solidified their impressive 21-3 record but also marked a significant milestone for the school as they clinched their first-ever AAA Long Island title.

Syosset is heading to its first-ever New York State final four this weekend on the heels of an incredibly deep team where three middle schoolers sharpen the skills of the more seasoned athletes.

“They do what’s expected of them to the highest level, and it’s really allowed the team to shine,” head coach Mike Ferreira told The Post ahead of facing Syracuse suburb Liverpool at Hudson Valley Community College upstate in Troy on Saturday afternoon.

Building the program up from the ground level, especially encouraging the new recruits to thrive when they got in the game, is something senior leaders such as Kate Nelmes genuinely takes to heart.

She even boasted that middle schoolers on scout team played a key role in prepping for Brentwood.

“We’ve gone through great role models [in the past], and I think we’ve learned from them,” Nelmes said, adding that many team alumni were in the stands of the LI championship.

“We try to represent some of those qualities,” she added of making the young teammates feel significant.

Ball in the family

Julia Schneider, a seventh-grade guard, is having the time of her life alongside older sister Samantha, an 11th-grade guard who scored 26 crucial points in the LI championship.

“I like playing with my sister, I feel like this just gets me better,” said Julia, who this week has an important role as a scout player imitating Liverpool’s tactics after a crash course of watching film on the opponent they have never faced.

Samantha, who has been a leader in mentoring not just her sister but the entire team, is also cherishing the special family moment that’s upcoming.

“Who knew even I was going to make it there? The fact that we get to go together is incredible,” she said.

Revenge tour

A lot changed for Syosset after the highs and lows of 2024.

Yes, the team won its first-ever Nassau County title, beating juggernaut Baldwin 49-44, but came up short to a strong Walt Whitman in a 38-29 loss for the LI championship.

“It felt like last year after we won the Nassau championship for the first time, we were just happy to be there,” Ferreira said. “It was a game that we lost that I felt that we shouldn’t have.”

There was an entirely different attitude this time as everyone “bought in” to finish the job, especially after topping rival Plainview-Old Bethpage 62-53 for the county title.

Senior standout Nelmes is proud that showing true grit, especially after last season’s crushing end, has been the team’s new mantra.

“Our team knows how much work we put in every single day. We don’t take a day off,” she said.

“Whether it’s film, weight room, or practice, we’re always making sure we put in the work. And to see it paid off after the many months we put in, it feels amazing.”

The months of preparation, which these winter athletes started in the summer, brought emotional maturity to the team at a time when it needed it most — trailing Brentwood while heading into the fourth quarter.

“We had that mindset where we’ve been there before, and we know what it takes,” said Nelmes, who played a major role in the comeback.

“Even when we were down, we knew we could win.”

Now, back in the driver’s seat, nobody on Syosset is just happy to be there this time.

A huge “Beat Liverpool” digital sign hung during a conditioning workout in the team’s weight room on Tuesday.

“Since February, we’ve been practicing seven days a week,” Samantha Schneider said.

“We’re mentally ready and don’t fear girls bigger than us or stronger than us, and we know we can compete with them again and again. … This team really wants it.”