Newcastle United owner Mike Ashley "created a disturbance in a bar" in Dubai a decade ago and ruined a potential sale of the club, a businessman has alleged during the latest stage of a High Court dispute.
Mr Ashley, who also owns sportswear firm Sports Direct, has sued former Charlton Athletic co-owner Tony Jimenez over a 2008 French golf course deal.
He has accused Mr Jimenez of perpetrating fraud and has made a forgery complaint.
Mr Jimenez, a former Newcastle United vice president, disputes his claim.
A judge is analysing pre-trial issues at a High Court hearing in London, starting on Tuesday.
A barrister leading Mr Jimenez's legal team told the judge, Chief Master Matthew Marsh, about the 2008 "disturbance" at the Bahri Bar in a written case outline.
Adam Johnson QC said Mr Ashley's "basic complaint" was that he was entitled to be repaid £3 million he handed over with the aim of acquiring an indirect interest in the Les Bordes golf course development.
He said Mr Ashley had given instructions for £3 million to be paid into a nominated company account, but had subsequently agreed that the money should be "retained" in relation to work Mr Jimenez had done trying to find a buyer for Newcastle United.
Mr Johnson said Mr Ashley also agreed to hand over another £7 million.
"Mr Jimenez's evidence is that he did a lot of work on the Newcastle United Football Club sale and became increasingly concerned by Mr Ashley, who refused to meet a potential buyer - who went on to purchase Manchester City Football Club," said Mr Johnson.
"He lined up some further potential buyers and Mr Ashley then visited Dubai between 13 and 18 September 2008 in order to meet them.
"Mr Jimenez says that on the evening of 16 September 2008, Mr Ashley created a disturbance in a bar in Dubai.
"Although Mr Jimenez helped Mr Ashley minimise the impact of the trouble, it again ruined the potential sale of Newcastle United Football Club that Mr Jimenez had lined up."
Mr Johnson said that a day later, Mr Ashley agreed that, in addition to the £3 million already paid, the company account would receive another £7 million.
He said Mr Jimenez had told how terms were recorded in a letter agreement.
Mr Ashley disputes Mr Jimenez's account. He says he has "no knowledge of the 17 September agreement" and claims it was a forgery.
Lawyers representing Mr Ashley said he was entitled to have the £3 million repaid.
Barrister Richard Lissack QC, leading Mr Ashley's legal team, said in a written case outline that £3 million had been transferred "at Mr Jimenez's direction for him to hold" for Mr Ashley for the "agreed purpose of securing a shareholding in Les Bordes".
Mr Lissack added: "Since that purpose has not been fulfilled, Mr Ashley is entitled to the repayment of such monies."
He said it was "inherently improbable" that Mr Ashley would have "agreed to have gifted Mr Jimenez £10 million, "even if Mr Jimenez had assisted in relation to the incident at the Bahri Bar".
Five years ago, Mr Jimenez was involved in a similar dispute with ex-Chelsea and England footballer Dennis Wise.
A judge ruled in Mr Wise's favour in 2013 after a High Court hearing in London.
Mr Lissack said the "fraud perpetrated by Mr Jimenez" on Mr Ashley was "very similar to one perpetrated by him upon Mr Dennis Wise".
Mr Wise had said he gave "former close friend" Mr Jimenez £500,000 to invest in the same French golf course development.
He claimed the agreed purpose was not fulfilled and he was entitled to have the money back.
Mr Jimenez disputed Mr Wise's claim and said the money was invested in the golf course development in Les Bordes as agreed.
Judge Penelope Reed ruled in Mr Wise's favour and ordered Mr Jimenez to pay compensation.
The two men used to work together at Newcastle United - Mr Wise was director of football and Mr Jimenez was a vice president.