During an Ask Me Anything session on Reddit on Monday a fan asked the 28-year-old if she could beat the boxing champion in a "ruleless" fight. Rousey admits that Mayweather would "definitely" beat her in the boxing ring, but on her own turf?
"I unfortunately don't get into 'matches.' I fight for a living," she wrote to the fan. "In a no rules fight, I believe I can beat anyone on this planet."
She added: "Boxing is a sweet science with strict rules that I respect very much and aspire every day to improve at. But you said ruleless fight, and that's my honest answer."
The jab is the latest in Rousey's feud with the boxer stemming from a 2014 interview when Mayweather said, referring to Rousey, "I don't even know who he is."
Rousey commented on the remark more than a year later at the 2015 ESPYS in July where she took home the award for best fighter (beating out Mayweather).
"I wonder how Floyd feels being beat by a woman for once," she told reporters, according to ESPN. "I'd like to see him pretend to not know who I am now."