Floyd Mayweather Jr. has maintained his 10th-round TKO of Conor McGregor would be his last professional fight.
Now his son is backing him up.
Mayweather's son, Koraun, told TMZ Sports there is "no chance" of a rematch between the two fighters.
"Officially done. He's 40, gotta realize that. He's an old man," Koraun said.
Mayweather came out of a 23-month retirement to defeat McGregor on Saturday in what could be the highest-grossing boxing match in history. The fight itself was more spectacle than great boxing match—McGregor was making his professional boxing debut—but it generated extreme hype because of the star power involved.
"This was my last fight tonight," Mayweather said afterward. "For sure. Tonight was my last fight. Tonight I chose the right dance partner to dance with. Conor, you are a hell of a champion."
Mayweather retires with a 50-0 record, breaking a tie with Rocky Marciano. While it's a trope that boxers are never fully retired—Mayweather himself has "walked away" on multiple occasions—there is no real incentive for him to get back in the ring.
His fight with McGregor will net him another nine-figure payday, and it made him the third professional athlete to ever pass $1 billion in career earnings (Tiger Woods, Michael Jordan).
There is no obvious opponent who would guarantee Mayweather another $100 million, and the odds are overwhelmingly against a return to fight the winner of the Canelo Alvarez-Gennady Golovkin bout Sept. 16.