Amanda Nunes Says If Cyborg Wanted Rematch She Wouldn't Have Left UFC

Amanda Nunes is calling BS on Cris Cyborg ... telling TMZ Sports the former UFC champ NEVER would've left the UFC if she really wanted a rematch with the champ-champ.

Nunes -- the bantamweight and featherweight champion -- came by the office this week with her fiancee (and #5 ranked UFC strawweight) Nina Ansaroff ... and chopped it up about Cyborg.

Remember, Cyborg -- who was KO'd in the 1st round of her December 2018 fight with Nunes -- floated the idea of a UFC-Bellator cross-promotion fight in the future when we saw her at LAX last month.

But, straight up, Nunes ain't buying it.

"Honestly, I love a challenge, but she made a wrong decision. She left [UFC], why? Why? If she really wanted to fight me she should’ve stayed."

Amanda says if Cyborg truly wanted the fight, she would've done anything -- including staying with the UFC -- to make the fight happen.

"If [Cyborg] really wanted [the fight], [she'd say] 'I’ll fight Amanda, give me $10,000 dollars. I'll fight her for $10,000. I’m better than her, I want that belt back.'”

So, Amanda thinks Cyborg's lying ... but it probably doesn't even matter.

The UFC hasn't done a cross-promotion in over 15 years ... and then there's the whole issue of Dana White despising Cyborg.