Ronda Rousey has been backed to "make noise again" in mixed martial arts by Floyd Mayweather.
Rousey had been unbeaten in 12 professional fights - winning 11 in the first round - before losing her UFC women's bantamweight championship to Holly Holm on Sunday.
Holm emerged victorious by knocking out Rousey in the second round at UFC 193 in Melbourne.
After the fight rapper 50 Cent posted an image mocking Rousey's defeat on Instagram, claiming Mayweather - the retired unbeaten former welterweight boxing champion - had instructed him to do so.
However, Mayweather told Fighthype.com: "I haven't really spoke to anyone about the Ronda Rousey situation, just to set the record straight.
"I don't have anything against MMA fighters. It's just like boxing; you win some, you lose some. A true champion can take a loss and bounce back.
"I don't think it's cool how everyone is trolling her on social media. Certain things you have to learn.
"People will love you on Friday and then Sunday morning, it's nothing but negative comments and people making jokes and people making fun about you, which I don't think is cool.
"I'm pretty sure she's a very, very strong person, but we still have to take into consideration that she has feelings. Everything happens for a reason. This was already written.
"Listen, if God says, 'In Floyd's career, I don't want him to lose', you know what? I wasn't going to lose. That doesn't mean that I haven't took a loss before.
"I'm not talking about boxing; I'm just talking about life. When you lose a loved one, that's taking a loss. I think that everything is just a learning experience. In due time, she'll be able to bounce back and make some noise again in mixed martial arts."
Rousey and Mayweather have previously been exchanged in a public war of words.
Mayweather said he did not know who Rousey was back in 2014. The 28-year-old responded after winning the Best Fighter award at the ESPYs ahead of Mayweather earlier this year by referencing his previous domestic violence convictions.
She said: "I wonder how Floyd feels being beat by a woman for once? I'd like to see you pretend to not know who I am now."