EXCLUSIVE

Ronda Rousey has a message for Laila Ali -- BRING IT ON!!!!

The undefeated UFC champ has just responded to Muhammad Ali's daughter (an undefeated ex-pro boxer) who told TMZ Sports no woman alive could beat her in a fight ... including Rousey.

In fact, when we shot Ali earlier this week ... she took a shot at Ronda's size -- saying, "She’s like the size of my daughter, my 3-year-old."

So, how does Rousey feel about that?

"If she wants to take me up on that, I’m around," Rousey told the Daily Beast.

"She’s retired and has several kids. I understand why she’d think that because she has a size advantage, but if you saw my last fight it had nothing to do with size or strength at all. That’s not how I beat people."

"So you can’t count having a size and strength advantage as having a real advantage against me."