STAN Ternent claimed during police questioning that his alleged victim had an "axe to grind", the court was told.
Jurors were read a transcript taken from a taped interview following the ex-Burnley manager's arrest two days after the incident.
During the interview with PC Rebecca Thompson Ternent claimed Greg Wilson was "upset" about his father being sacked from Burnley FC by Chris Waddle.
Ternent, who said he "wasn't a big drinker" and had only had half a can of lager on the day of the alleged attack, said that Mr Wilson had a vendetta.
He said during the altercation at Burnley Cricket Club he was subjected to a "torrent of abuse" by Mr Wilson who was swearing and insulting him.
During interview at Burnley Police Station he said to officers: "The only reason for him to say that was because I didn't give his dad a job at Burnley Football Club. That is the only thing I can think of.
"It wasn't my fault. I explained that if I could have employed him I would have done."
He said up until that day he and Harry Wilson had been "good friends" who played golf together and he had visited his home in Cliviger.
Ternent added: "He was very upset about being dismissed when Chris Waddle was manager of Burnley."
During the interview the tape had to be stopped when Ternent became emotional, the court was told.
He admitted headbutting Mr Wilson but said it wasn't pre-meditated, the court heard.
He said he shouldn't have reacted in that way and "regretted" the incident, the court was told.
His reply when cautioned and charged with actual bodily harm was that he was acting in self defence, the court heard.
Ternent, who is due to give evidence today, was supported in court by his wife Kath and Sam Ellis, his assistant during his six-year spell at Turf Moor.
Jurors are also expected to hear written evidence from Manchester United manager Sir Alex Ferguson and Gordon Taylor of the Professional Footballers' Association.
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