GUARDIAN - MMA star Ronda Rousey reckons she earns more per second than Floyd Mayweather - and she doesn't think much of his literacy, either.

A few weeks after saying she could take Mayweather in a no-holds-barred bout, the UFC champion suggested she was the real money-making machine in combat sports.

Rousey was stopped in LA by TMZ Sports, and told them: "I think I actually make two to three times more than he does per second ... so when he learns to read and write, he can text me."

Rousey added: "Floyd said '(When) you make US$300m a night, then you can give me a call' ... and I actually did the math, and given the numbers of my last fight, I'm actually the highest-paid UFC fighter. And I'm a woman."

When pressed by TMZ on whether she makes more than Mayweather does, Rousey said: "Yeah. I'm just more efficient."

Earlier this month, Mayweather remarked to ESPN on how much money he made this year. "I've yet to see any MMA fighter, or any other boxer, make over US$300m in 36 minutes," Mayweather said. "When she can do that, then call me."

Rousey has teased Mayweather recently, claiming in early August that she could beat boxing's biggest champion in a no-rules mixed martial arts-style fight in the octagon.

And in July, after she won an ESPY award for best fighter, for which Mayweather was a nominee, she said: "I wonder how Floyd feels being beat by a woman for once. I'd like to see him pretend to not know who I am now."

Rousey said she had been waiting for the right opportunity to call out Mayweather, who in a July 2014 interview said: "I don't even know who he is."

Rousey is the only women's bantamweight champion in the UFC's history. A two-time US Olympic judoka, she has dominated her new sport.

She defended her title by knocking out Bethe Correia only 34 seconds into the first round at UFC 190 in early August.