Pacquiao (left) and Mayweather have been unable to settle their differences
Floyd Mayweather Jr is "thoroughly disgusted" at the suggestion that he is to blame for the collapse of a super-fight against Manny Pacquiao.
The bout was declared dead in the water by Pacquiao's promoter Bob Arum on Wednesday after a mediator failed to salvage an agreement between the camps.
A row over drug-testing methods is the cause of the ongoing disagreement.
"I'm thoroughly disgusted Manny and his representatives are trying to blame me," said Mayweather.
"Clearly they are to blame. Throughout this whole process I have remained patient."
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 13 March showdown in Las Vegas, claiming such actions were defamatory.
With the fight in jeopardy, judge Daniel Weinstein was brought in to mediate in an attempt to solve the dispute - but ultimately failed to reach an agreement between the camps.
Mayweather said: "First and foremost, not only do I want to fight Manny Pacquiao, I want to whip him.
"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.
"I am ready to fight and sign the contract. Manny needs to stop making his excuses, step up and fight."
A statement from Weinstein confirmed "in the end, the parties could not agree on a testing protocol acceptable to all."
A fight is still seen as possible by many commentators but Weinstein's comments back up Arum's belief that a bout in March is now highly unlikely.
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."