Amanda Nunes said she plans to ride her upward trajectory "to the moon" after making history with her UFC featherweight title victory over Felicia Spencer on Saturday.

Nunes (20-4) became the first UFC fighter to defend belts in two weight classes while holding both titles by claiming a unanimous decision verdict after a dominant five rounds with Spencer.

The Brazilian, who is also the bantamweight champion and spent much of the fight with a smirk on her face, was delighted to prove her endurance by going the distance in a battle with a fierce competitor at UFC 250.

There are concerns that there no longer remains a female in the UFC capable of challenging Nunes' supremacy, and the 32-year-old does not envision her momentum stopping any time soon.

"I wanted to go five rounds with the most tough girl and tonight I proved it," Nunes said in a post-fight news conference.

"I knew Felicia is the toughest girl in this division and I knew she was gonna handle it exactly as she did. And I just wanted to prove it. I can go to six rounds, not only five anymore, and laugh, enjoy being there.

"Tonight was amazing, everything we worked on I was able to put in there. And that was making me laugh, not because I was hurting her, it's because I was able to put everything together that we were training on. Every fighter wants to do that ... and a lot of people can't and it's frustrating.

"But tonight was like it's always gonna be, because from here to the next I'm gonna grow. I'm gonna through the roof. I'm gonna go to the top of the mountain. I'm gonna go to the moon. Honestly, I'm going to go to NASA now!"

Nunes would not be drawn on who she sees as her next opponent, instead turning her focus towards some time off to welcome her first baby, which her wife is due to give birth to in three months, and have a leg injury investigated.

"A break for sure, I have to see what's going on with my leg, it always gets hurt," she said.

"And my baby is coming in three months. I have to organise so many things, her room, so many things. I think maybe off [for the rest of the year] for sure."

Despite suggestions of a lack of untested talent capable to truly test Nunes, UFC president Dana White believes the Brazilian can make more history if she desires.

White said: "I've told you guys many times, Amanda Nunes is the GOAT. Tonight she put on a clinic, you saw everything: power punches, she set the tempo, set the pace of the fight, did what she wanted when she wanted to do it, kicks to the legs, kicks to the body, kicks to the head, takedowns, takedown defence, elbows - everything that you could see in an MMA fight she put out there tonight.

"When you think about [next] opponents we think back to Anderson Silva, Jon Jones and many others [where] we were here having the same conversation: who's next? There's always somebody next.

"Not off the top of my head. She's at number eight [title fight wins] right now, three more and she ties Anderson Silva. Three more after that and she ties Jon Jones.

"It's gonna depend on how high she wants to set this bar and how long she wants to keep fighting, because she's made enough money to retire."