"I think the female that she faced was rugged and tough, so we can't take anything away from the female she faced. She was a tough competitor. She was the better woman that night."
But while many have called for Rousey to give the fight game away, Mayweather went another route.
"Ronda Rousey has a lot left, she has a lot left. I don't want her to think this is the end of the world," he said. "She's hearing it from the best - she'll be okay.
"Ronda Rousey, hold your head up. You're still a true champion in our eyes. You made women's MMA huge, so stay focused, go back to the drawing board and do what you've got to do. OK? 2017 is a whole new year ... you undefeated this year. Come back, champ."
Mayweather has returned to the media spotlight in recent days, visiting ESPN headquarters in Bristol to cover a range of topics, including whether he will stay retired - or fight UFC superstar Conor McGregor.
The man known as "Money" appears to change his mind in almost every interview on those two topics, and admitted as much.
"I've made mistakes. I'm not perfect," said Mayweather, during a Facebook Live interview with ESPN. "Can I contradict myself? Absolutely, because I'm only human. Floyd Mayweather's not perfect. God only mad one thing perfect - my boxing record."
But if he is to return it appears McGregor is the most likely opponent. "I'm an old man now so I'm smart," Mayweather said. "The best business move for me is Conor McGregor. That's what the world wants to see."
As for the boxing fight hardcore fans most want to see - a middleweight clash between "Canelo" Alvarez and Gennady Golovkin - Mayweather sees it going one way.
"Canelo's not ducking Triple G. Canelo will beat GGG," Mayweather said. "Triple G is the same guy who was just getting outboxed by a welterweight if (I'm) not mistaken.
"I know boxing. Nobody in the world knows boxing like me. Canelo knocks Triple G out. Triple G has his hands full with (Daniel) Jacobs (in March). Jacobs can fight."
