(CNN)He is back, and this time Floyd Mayweather Jr. is boxing for a shot at the history books.
The larger-than-life boxer -- known as "The Money Man" -- is hoping to break Rocky Marciano's haloed mark of 48-0 when he takes on former welterweight champion Andre Berto (30-3, 22 knockouts) at the MGM Grand in Las Vegas on September 12.
Coming off the biggest payday in boxing history following his $440 million pay-per-view generating match against Manny Pacquiao in May, Mayweather defended criticism of being a boring fighter and cruising to the finish line of his career by picking an easy opponent.
"Berto is a very, very tough guy, hungry and I know he is not going to lay down," said Mayweather at the press conference announcing the fight Thursday.
"I chose Berto because he is very exciting. Then I looked and then said, well I have been getting backlash, he's been getting backlash," added the 38-year-old Mayweather, who insists this will be his final bout, although some have their doubts.
"No one is forced to buy the fight. I appreciate it, but no one is forced to buy the fight."
In promoting the bout, Leonard Ellerbe, president of Mayweather Promotions, wasn't slow to mention that this might just be the last time the boxer steps into a ring.
"Come September 12, this is our last opportunity to see Floyd Mayweather. I know many people doubt that but trust me," said Ellerbe.
"This gentleman to my right, you better take a look at him, but things he's accomplished in this sport, you will never, ever see again," added Ellerbe.
The May 2 fight against Pacquiao, which Mayweather won on an unanimous decision, was largely seen as a flop in terms of excitement as the champion known for his defensive tactics deftly glided around the ring, with the two boxers hardly mixing it up over the 12 rounds.
"My job was to go out there and be Floyd Mayweather and be a chess player, and that's what I did and found a way to win," said the boxer about his tactics.
Mayweather called out the media for inflating Pacquiao's ability in his last fight, an ironic stance to take after his self-owned promotions company created much of the buzz -- with great success.
"Andre Berto is gonna push Floyd Mayweather to the limit, that's one thing that I do know" said Mayweather. "The difference between Andre Berto and Manny Pacquiao is that you guys put all the hype in Pacquiao, that's what the media did."
Mayweather, who will be defending three welterweight titles, spoke with a crackly voice that was at times barely audible.
"My voice is a little hoarse, you know I've been up late last night," explained Mayweather, who is known for sampling the nightlife in his hometown of Las Vegas.
Thirty-one-year-old Berto, an American who fought for Haiti in the 2004 Olympics, comes from a family of boxers, with his father, two brothers and two of his sisters all fighting professionally in the past.
One of this brothers, Edson "Little Tiger" Berto is an MMA fighter with a 17-12 record.
Berto will hope to replicate Buster Douglas's win over Mike Tyson -- the biggest upset in boxing history, which took place 25 years ago at the Tokyo Dome.
Heavyweight champion Tyson, 37-0 at the time, was seen as unbeatable, while Douglas was known only to the most fervent boxing enthusiasts.
That the match was fought in Japan, at noon local time to accommodate global audiences, speaks volumes about the fight's lack of drawing power in America.
An overconfident Tyson was knocked out by Douglas in the 10th round, and although "Iron Mike" would later regain his heavyweight belts, he was never again the same fighter.
Tyson would later recount being up all night in his hotel room before the fight.
"I guess I didn't have no respect for Buster Douglas as a fighter," he said, recently recalling his training for the Douglas fight to Playboy. "I was like the Floyd Mayweather of back then, pretty arrogant and stuff and saying what was on my mind without having a filter."
Mayweather will surely keep all that in mind before stepping into the ring on September 12, probably with more sleep than he got before the press conference.