Too bad the multi-division boxing champion wouldn't be able to distinguish Rousey from Adam.
"I don't know who he is," Mayweather said (at about the 36-second mark) during the following interview:
When explained that Rousey is a female UFC star, the boxer threw up his hands in bewilderment: "I ain't know who that is."
Are these fighting words?
UPDATE 7/18/2014: Mayweather apologized to the UFC champ. "I wish her a congratulations because I didn't know who she was," the boxing champ told FightHub TV. "I apologize because I didn't know. You know, I'm used to watching football and basketball ... I'm not really into boxing like that."