A Manhattan federal court trial kicked off Monday for a professional boxer once dubbed “Mini Mike Tyson” who the feds say had a secret side job using his pugilistic skills to serve as an “enforcer” and “soldier” to a Brooklyn mob boss.

In addition to being a WBO prizefighter, Avtandil Khurtsidze, 39, “was the man who bloodied others” on behalf of Brighton Beach mob boss Razhden Shulaya, prosecutors said at the opening of their joint racketeering trial.

“Shulaya acted as the boss and Khurtsidze acted as his solider,” prosecutor Andrew Thomas told the jury.

Khurtsidze, a middleweight, has been in federal lockup since his arrest last year and faces as a much as 40 years if convicted.

He sat slumped in his chair as prosecutors went through their evidence, including multiple security videos they say will show the boxer threatening or bloodying people on behalf of co-defendant Shulaya.

In one video, the jury is expected to see Khurtsidze stand up and punch a man directly in the face after he is accused of stealing money from a Brighton Beach poker ring Shulaya allegedly ran, court papers show. Shulaya then slaps the man’s face and tells him he had better pay up or be punished further, court papers say.

“You will hear threat after threat after threat,” Thomas said of Khurtsidze, who was known as “The Hammer” by Shulaya and other members.

Khurtsidze’s lawyer, Megan Benett, said the two men knew each other from their days in post-Soviet Georgia and that they “socialized together” — but were not in cahoots together. “We are confident the government’s case is going to leave you with reasonable doubts,” Benett said.

Shulaya stands accused of being the mastermind behind three illegal operations: the buying and selling of untaxed cigarettes, running an illegal poker ring that also cheated its players and hacking the code on slot machine software so that members of the alleged mafia could rig the winnings.

Shulaya’s lawyer, Jennifer Louis-Jeune, said the evidence will show that the feds were behind Shulaya’s shenanigans, including selling him the untaxed cigarettes mentioned in the indictment and coughing up the dough needed to buy them off him as well.