The "fight club" scrap at a Queens elementary school was uncovered only after the father of one of the combatants heard his son whining that he didn't have enough fans in his corner.

Tomas Rivera said that he overheard his son complaining to his sparring partner — as the pint-sized pugilists played video games Thursday evening — that he wasn't getting enough applause during their bout at PS 65 in Ozone Park.

"I heard him go, 'Oh, they were cheering you more than they were cheering me,' " the father told The Post.

Rivera then quizzed his son, also named Tomas, and the 10-year-old spilled the beans about the clash, which was allegedly set up by Joseph Gullotta, the kids' fourth-grade teacher.

Rivera said his son initially had a beef with another student when Gullotta told the boy, "Don't fight with him because I like you guys too much."

Instead, the teacher allegedly told his son to take out his aggression on longtime pal Justin Stokel, 9.

"Mr. Gullotta told him, 'You are my favorite star student, why don't you start a fight with him instead?' "

During the match, the kids butted heads, leaving Stokel with a split lip and Rivera's kid with a possible concussion.

Like in the flick "Fight Club," Gullotta allegedly told the boys not to spill the beans and supplied them with a phony story to tell the school nurse — that they bashed their heads together accidentally as they both bent over to pick up a fallen pencil.

Rivera said that if he hadn't caught wind of the kids' conversation, the brawl would have gone undetected.

"He wasn't going to snitch on his teacher," Rivera said of his son. "He really respected him."

Rivera reported the incident to school officials the next day and then went to the cops.

"The police found it so strange and unorthodox that they arrested him," Rivera said.

Both families have hired lawyers who say they intend to file a notice of claim against the city.

Gullotta, a teacher since 2004, and Abraham Fox, 43, a 20-year para-professional who allegedly helped supervise last week's scuffle, were charged with acting in a manner injurious to a child under 17. They each face up to a year in prison if convicted.

Parents received letters yesterday from the school saying that both men have been reassigned pending an investigation.