Boxer Carl Frampton is claiming £6m in lost earnings from the time Barry McGuigan was his manager, a court has heard.
Appearing at Belfast High Court on Thursday, Mr Frampton denied suggestion he was being "greedy".
He insisted he was simply trying to get back money he felt he was owed.
The former world champion is suing Mr McGuigan and the firm Cyclone Promotions (UK) Ltd over alleged withheld earnings.
Mr McGuigan has counter-sued, accusing Mr Frampton of a breach of contract. Both men deny any wrongdoing.
'Don't know how much I'm owed'
On the third day of legal proceedings, Liam McCollum QC put it to the boxer that legal documents suggest he is seeking £6m.
Mr Frampton responded: "I don't know how much I'm owed."
He said he had employed a forensic accountant to look into his earnings.
"I want what I'm entitled to," he added.
He was asked by the barrister if he was a greedy person.
"I'm not a greedy person," he insisted.
Mr Frampton said that before his partnership with Mr McGuigan broke down in the summer of 2017, he had trusted him and his family "wholeheartedly".
He added: "Brainwashed may be a strong word. But I believed everything these people told me."
The boxer was also questioned about comments made at the start of the case, comparing his partnership with the management company to a "slave contract".
'Shouldn't have signed'
Mr McCollum said being a slave meant doing things you do not want to do, but suggested to Mr Frampton that he fought willingly.
Mr Frampton said he regretted not looking more closely at his contractual arrangements.
"I signed things I shouldn't have signed," he said.
The case, which is into its third day of proceedings, is expected to last two weeks.