UFC women's bantamweight champion Amanda Nunes continues to track at becoming one of the best women's fighters in the world on Saturday night in Rio de Janeiro, Brazil, when she takes on Raquel Pennington in the main event of UFC 224. The fight on its own should be enough to grab fight fans' attention, but the battle has even more intrigue given the friendship the two fighters share.

It's Nunes' second straight fight headlining a PPV after she won a unanimous decision over Valentina Shevchenko in September 2017. There's also the lingering discussion about Nunes taking on fellow Brazilian champion Cris "Cyborg" Justino in a superfight if she's successful against Pennington. 

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Plus, we get the return of Kelvin Gastelum when he takes on middleweight veteran Ronaldo "Jacare" Souza. Gastelum is coming off a vicious first-round knockout of former middleweight champion Michael Bisping in November and looking to inch closer to his first ever title shot. Plus, it's the return of top women's strawweight prospect Mackenzie Dern when she takes on Amanda Cooper -- fresh off her debut victory in March.

Check out the rest of the card and fight order for Brazil below.

FavoriteUnderdogWeghtclass

Amanda Nunes (c) -600 

Raquel Pennington +400

Women's bantamweight title

Ronaldo Souza -150

Kelvin Gastelum +120

Middleweight

Mackenzie Dern -235

Amanda Cooper +185

Women's strawweight

John Lineker -250

Brian Kelleher +195

Bantamweight

Lyoto Machida -260

Vitor Belfort +200

Middleweight

Karl Roberson -155

Cezar Ferreira +125

Middleweight

Junior Albini -140 

Aleksei Oleinik +110

Heavyweight

Davi Ramos -140

Nick Hein +110

Lightweight

Elizeu Zaleski dos Santos -135

Sean Strickland +105

Welterweight

Warlley Alves -250

Sultan Aliev +195

Welterweight

Jack Hermansson -160

Thales Leites +130

Middleweight

Ramazan Emeev -200

Alberto Mina +160

Welterweight

Markus Perez -285 James Bochnovic +225 Middleweight