Barry Bennell used a "Darth Vader grip" to pin a youth footballer to a wall after he interrupted the former coach abusing a boy, a court has heard.
Martin Clarke said he had seen Mr Bennell with one of his alleged sex abuse victims in the changing rooms at Crewe Alexandra's Gresty Road ground.
Liverpool Crown Court heard claims he threatened to "finish" Mr Clarke's football career if he told anyone.
Mr Bennell, 64, denies sexually abusing 11 boys between 1979 and 1990.
Mr Bennell, now known as Richard Jones, has admitted seven further charges of indecent assault.
Giving evidence in court, Mr Clarke said he returned to the ground after forgetting his football boots following a game and had "startled" Mr Bennell.
He said: "He jumped up, stormed at me and pinned me to the wall. If you can imagine Star Wars and Darth Vader, it was like a Darth Vader grip."
Mr Clarke said the young boy ran out of the changing room and Mr Bennell then told him: "You have not seen anything. If you say anything to anyone I will make sure I will finish your football career here and now."
He told the jury that Mr Bennell had a "psychological hold" over him after that incident.
The court also heard from an alleged victim of Mr Bennell who claims he was abused up to 100 times by the former coach, including in Gresty Road's changing rooms.
He also told the jury he was abused at Mr Bennell's home, a video shop which the coach owned and on a trip to Butlins.
In cross-examination by Eleanor Laws QC, defending, the complainant denied having discussions about claiming compensation, saying: "I don't think anything would compensate that anyway."
He did agree he wished to claim damages against Crewe and the Football Association.
But the complainant described as "ridiculous" the lawyer's suggestion that he had made up his claims "either for money or whatever reason".
The trial continues on Thursday.