Floyd Mayweather announced that he would face kicker Tenshin Nasukawa on New Year's Eve.
The legend of boxing pound-to-pound had to face the Japanese in a sensational return to the ring.
The rules of the surprise contest had not yet been defined, the Rizn Fighting Federation having announced last week that the fight was about to unfold.
But Mayweather took on Instagram to confirm that an agreement had never been reached.
He insists that the original proposal that was presented to him consisted of an exhibition of only 9 minutes to be "caught unawares" by the announcement of a fight with Nasukawa.
Mayweather was photographed with Nasukawa in Tokyo last week, the image apparently confirming that a fight was in place.
It took several days for the American to announce that his return would not be felt, much to the disappointment of his fans.
Mayweather also appeared to put an end to speculation that he would also face Manny Pacquiao in a rematch.
The speculation is going well, and the two men will face each other again. Pacquiao insists this week on the fact that he was confident of being able to qualify.
But Mayweather insisted that he was "retired" in his Instagram post for his fans.
Pacquiao responded to Mayweather's announcement with a series of emoticons on Twitter before the American did not make fun of Rizin.
"Floyd must have seen that Tenshin is highlighting the reel," they posted.
Now that I am back on American soil after a long and disappointing trip to Tokyo, I now have time to speak to you, my fans and the media, about the event announced on December 31st.
First, I want it to be clear that I, Floyd Mayweather, have never accepted an official fight with Tenshin Nasukawa.
In fact (with all due respect), I have never heard of him until this recent trip to Japan.
Finally, I was asked to participate in an exhibition of 3 rounds of 9 minutes with an opponent chosen by the "Federation of Rizen fighters". What Brent Johnson, originally from "One Entertainment", had originally said, was for the price of an exhibition intended for a small group of wealthy spectators, for a very high price.
Previously, this exhibition was organized as a "special fight" only for entertainment purposes, with no intention of being portrayed as an official or televised fight card around the world.
Once at the press conference, my team and I were completely disappointed by the new direction taken by this event and we should have ended it immediately.
I would like to sincerely apologize to my fans for the very misleading information that was announced during this press conference and I can assure you that I, too, have been completely blinded by the arrangements that have been made without my consent or my approval.
For the pleasure of the many fans and participants from all over the world to attend the previous press conference, I was hesitant to create a huge mess by fighting what was being said and for that I'm really sorry.
I am a retired boxer who earns an unprecedented amount of money, worldwide, for appearances, speaking engagements and occasional small shows.