An ex-St. John’s University lacrosse player who was stabbed in the guts by a former teammate during a house-party brawl over loud music recalled the bloody incident Monday during his alleged assailant’s assault trial in Queens.

Justin Corpolongo looked shaken as he described the lead-up to the brutal 2019 fight with his then-roommate Matthew Stockfeder — whose lawyer said that he used the knife only in self-defense after Corpolongo started the fight.

Corpolongo — who was left with his “intestines . . . hanging out of his stomach” according to Assistant District Attorney Konstantinos Liturgis — said the incident began when he came home after a long shift bartending and found his home the scene of a house party with roughly 20 guys blasting music.

“My room was directly below the floor where they were having a party,” said Corpolongo, who graduated in 2018 and now works as a teacher.

After politely asking them to turn the sound down, Corpolongo said he “went upstairs and pulled the power cord out of the speaker.” 

Corpolongo, whose parents were in Queens Supreme Court to support him, stared at Stockfeder as he testified.

Close to 40 people came to back Stockfeder, 24, on the first day of his felony assault trial.

Richard Sullivan, the first witness to take the stand, told the jury how the ex-lacrosse captain and the rest of the partyers showed up at his house later that night.

He said Stockfeder grabbed a steak knife from the kitchen and showed it off after placing it in his waistband.

“I asked him ‘why does he have that [knife]?’ and [Stockfeder] replied ‘to defend myself,’ ” Sullivan told the jury.

Stockfeder “was holding his phone with both hands and looked like his face was buried in it,” Sullivan described.

He “antagonized” Corpolongo in a group text, the ADA said.

Corpolongo then arrived, squaring up against Stockfeder and throwing the first few punches, Liturgis said.

Two lacrosse players stepped in to break up the brawl — which is when Stockfeder “took a knife from his waistband and plunged it not once but twice into his [ Corpolongo’s] lower abdomen.”

Defense attorney Michael Douglas Horn argued his client “reacted out of fear,” while the victim “reacted out of rage.”

Corpolongo is expected to describe the fight and stabbing when he continues testifying on Tuesday. The trial is set to last four days.

Per: NYP