Floyd Mayweather Jr insists he is "thoroughly disgusted" by claims he is to blame for the collapse of a lucrative super-fight against Manny Pacquiao.
The mediator charged with salvaging the high-profile showdown admitted last night the rival teams have failed to reach an agreement.
Pacquiao's promoter Bob Arum announced on Wednesday night a fight between his fighter and Mayweather was dead in the water after negotiations broke down over an ongoing row over drug testing.
Filipino fighter Pacquiao issued legal proceedings last week following Mayweather's insistence on ultra-stringent doping testing - namely the taking of blood samples close to the fight - for their proposed March 13 showdown in Las Vegas, claiming such actions were defamatory.
With the fight therefore in jeopardy, a mediator was brought in to attempt to solve the dispute this week. Arum claimed Mayweather and his team were unwilling to negotiate and the fight was off.
Mayweather, however, insists he has been - and remains - more than willing to compromise.
"Throughout this whole process I have remained patient, but at this point I am thoroughly disgusted that Pacquiao and his representatives are trying to blame me for the fight not happening when clearly the blame is on them," he said.
"First and foremost, not only do I want to fight Manny Pacquiao, I want to whip his punk ass.
"Before the mediation, my team proposed a 14-day, no blood testing window leading up to the fight.But it was rejected. I am still proposing the 14-day window but he is still unwilling to agree to it, even though this is obviously a fair compromise on my part as I wanted the testing to be up until the fight and he wanted a 30-day cut-off."
Mayweather added: "I am ready to fight and sign the contract. Manny needs to stop making his excuses, step up and fight."
A statement released last night by Golden Boy Promotions - who represent Mayweather - quoting "an order to correct the false record that has been created by the recent statements from Top Rank and Manny Pacquiao's representatives" by mediator Judge Daniel Weinstein, said: "The mediation was a confidential proceeding.
"Any comments to the press or public by participants in the mediation purporting to report the substance or details of the mediation are violations of the strict confidentiality to which the parties and their representatives agreed and which they authorised the mediator to enforce.
"The parties and their representatives authorised that, if misinformation was disclosed to the press by either side, the mediator would correct any erroneous information."
According to Golden Boy's release, Weinstein then clarified the mediation process was participated in by both parties "in good faith" and insisted Weinstein himself did not put forward a 'mediator's proposal' for either side to either accept or reject.
Crucially, however, Weinstein's statement confirmed that "in the end, the parties could not agree on a testing protocol acceptable to all."
While there remains a good chance the fight will go ahead despite all the negotiating bluster, Weinstein's statement backs up Arum's assertion the fight is currently in doubt to say the least.
The veteran Top Rank promoter had dramatically stated: "There is no chance ever of salvaging it for March. There's no chance for it ever to happen."