Mayweather, undisputed pound-for-pound king of the world, unbeaten after 48 fights, insists he will duck under the ropes for the final time following the bout.
A victory would equal Rocky Marciano's record of 49 unbeaten fights, yet Mayweather says he's ready to call it quits before taking the record for himself: "I'm not going to miss it at all", he explained, "...I'm just ready to see somebody else at the top. I've done it all, I've made hundreds of millions in the sport."
If it proves to be his final fight (some believe it is being billed as such for marketing purposes), there will be no Rocky-movie ending to Mayweather's career. No iconic, climatic blow out for the veritable all-time great of the sport.
The build-up for the Mayweather's last stand has been marked by slow ticket sales, a sharp drop in anticipated revenue and even revelations surrounding banned injections taken before the recent mega-fight with Manny Pacquiao in May.
Mayweather's choice of Berto as an opponent - a 16/1 outsider who has lost three of his last six fights - was met with cynicism by boxing fans weary with dominant but rarely enthralling Mayweather contests.
Certainly there is little clamour to say goodbye in person. Tickets priced between $1,500 - $10,000 for the Pacquiao match sold out in two hours of being publicly available.
In contrast, tickets for the Berto match - around 90 per cent cheaper in some seats - were still available as close to the fight as Thursday morning. Even Anthony Joshua's fight in London this weekend has done better numbers on online secondary ticket marketplace StubHub.
Numbers for pay-per-view TV buys have also shrivelled to a third of the $400m generated by the Pacquiao clash, according to the Daily Mail, which would see the fight generate around $100m.
Yet if the Mayweather camp could have anticipated a lukewarm reaction following his choice of opponent, the revelation that he was administered banned intravenous vitamin injections the day before fighting Pacquiao would have been less expected.
An investigation into boxing's relationship with the U.S Anti-Doping Agency (Usada) found that the authority had found evidence of Mayweather receiving the IV - banned by the World Anti-Doping Agency - but did not inform the Nevada State Athletic Commission.
Mayweather's team say the saline and vitamin mix was given to the boxer to treat dehydration. There is no allegation of cheating, yet having your name in headlines on doping investigations is not what fairy tale farewells are made of.
Yet as always with the man who calls himself "Money", the impression is that none of that will bother him too much. The $32m expected to enter his bank account appears much more important than retiring in style.
After winning a world title at 45 years old George Foreman said: "The question isn't at what age I want to retire, it's at what income."
Despite the controversy and cynicism, that's one question Mayweather won't have to worry about before hanging up his gloves.