When Amanda Nunes steps into the Octagon on Saturday night for the main event of UFC 250 in Las Vegas, it will be the first time she will be defending the women's featherweight championship she won in December 2018.

Please excuse her inattention to the 145-pound division. Nunes (19-4, 12-1 in the UFC) has been busy fending off challengers for her other title -- in the bantamweight division.

Now the 32-year-old Brazilian is focused again on featherweight, and standing in front of her will be Felicia Spencer (8-1). The challenger is only 2-1 in a UFC run that began last year, but the former Invicta FC featherweight champion showcased her MMA bona fides in that lone career loss, a rugged decision defeat against Cris Cyborg. Spencer let the world know that night in July 2019 that she is a true 145-pound contender.

Nunes has been in the cage with Cyborg too -- briefly. That was the night she became a two-division champ, knocking out her indomitable countrywoman in a frenetic and frightening 51 seconds. It ended a 21-fight unbeaten run by Cyborg that extended all the way to 2005. It was Nunes' second quick finish of an all-time great. Almost exactly two years earlier, she demolished Ronda Rousey in 48 seconds. Rousey has not been seen again in MMA.

For those two victories alone, Nunes is widely acclaimed as the greatest fighter in the history of women's MMA. She has won 10 fights in a row, seven by finish.

UFC 250, which will take place at the promotion's Apex facility with no fans allowed because of the coronavirus pandemic, also will showcase the men's bantamweight division. Four of ESPN's top 10 will be in action -- including a bout between No. 3-ranked Aljamain Sterling and No. 6 Cory Sandhagen that could determine who gets to step forward and challenge for the 135-pound title.

But this night is about a current champ who rules women's MMA. Nunes will be looking to further secure her place on the top of the mountain. A mountain with two peaks.

By the numbers

12: UFC victories by Nunes, the most in promotion history by a female fighter.

2: Canadians who have been UFC champions (Georges St-Pierre, Carlos Newton). Spencer, who was born in Montreal, is seeking to be the third.

+475: Betting odds on Spencer, the second-longest odds for a Nunes opponent (behind Raquel Pennington's +525 in May 2018). With a win, Spencer would pull off the second-biggest upset in UFC women's title fight history, behind +875 underdog Holly Holm's knockout of Ronda Rousey in November 2015.

7: Title fight victories by Nunes, the most ever among UFC women and fourth most among all active UFC fighters, behind Jon Jones' 14, Anderson Silva's 11 and Jose Aldo's 8.

0: Betting favorites who have won main events since the UFC began staging fight cards in venues with no fans in attendance. Charles Oliveira (+120) kicked off the run of upsets on March 14, followed by Justin Gaethje (May 9, +180), Glover Teixeira (May 13, +160), Alistair Overeem (May 16, +115) and Gilbert Burns (May 30, +140). This would seem to bode well for Spencer, although she is a far bigger underdog than the others, at +475.

Sources: ESPN Stats & Information and UFC Stats

Five vs. five

Amanda Nunes' most recent results
Win: Germaine de Randamie (UD, Dec. 14, 2019; watch on ESPN+)
Win: Holly Holm (TKO1, July 6, 2019; watch on ESPN+)
Win: Cris Cyborg (KO1, Dec. 29, 2018)
Win: Raquel Pennington (TKO5, May 12, 2018)
Win: Valentina Shevchenko (SD, Sept. 9, 2017)

Felicia Spencer's most recent results
Win: Zarah Fairn (TKO1, Feb. 29, 2020; watch on ESPN+)
Loss: Cris Cyborg (UD, July 27, 2019; watch on ESPN+)
Win: Megan Anderson (SUB1, May 18, 2019; watch on ESPN+)
Win: Pam Sorenson (SUB4, Nov. 16, 2018)
Win: Helena Kolesnyk (SUB2, July 21, 2018)

Dom & Gil's film study

Cruz and Melendez break down Amanda Nunes' power:

Cruz explains the importance of Felicia Spencer's scrambling:

Marc Raimondi's prediction

Nunes is the best female fighter in MMA history. It's hard to argue against that at this point. She's the UFC champion at bantamweight and featherweight, and she has beaten everyone else who has ever held those titles. Here, she's a heavy favorite -- the most she has been favored by since her 2018 fight with Raquel Pennington. Spencer is unproven; she has fewer than 10 career fights. What we do know about Spencer, though, is that she is durable and incredibly tough. She went the distance with Cris Cyborg last year at UFC 240. I think she'll do the same here with Nunes -- hang in until the end -- but the champ will win a fairly one-sided fight. Nunes by unanimous decision.

Saturday's fight card

PPV (via ESPN+), 10 p.m. ET
Amanda Nunes (c) vs. Felicia Spencer | Women's featherweight
Raphael Assunção vs. Cody Garbrandt | Men's bantamweight
Aljamain Sterling vs. Cory Sandhagen | Men's bantamweight
Neil Magny vs. Anthony Rocco Martin | Welterweight
Eddie Wineland vs. Sean O'Malley | Men's bantamweight
ESPN/ESPN+, 6 p.m. ET
Alex Caceres vs. Chase Hooper | Men's featherweight
Ian Heinisch vs. Gerald Meerschaert | Middleweight
Cody Stamann vs. Brian Kelleher | Men's bantamweight
Charles Byrd vs. Maki Pitolo | Middleweight
Alex Perez vs. Jussier Formiga | Men's flyweight
Alonzo Menifield vs. Devin Clark | Light heavyweight
Evan Dunham vs. Herbert Burns | Catchweight (150 pounds)

(c) = defending champion

What else to look for ... beyond the main event

Garbrandt has that old championship feeling back

Almost exactly four years ago, Cody Garbrandt sat down in a room at the old UFC headquarters in Las Vegas. It was his first time having a full-length conversation with UFC president Dana White and Lorenzo Fertitta, then the promotion's owner.

Garbrandt had just knocked out Thomas Almeida to move to 9-0. With good looks, charisma and huge power in his hands for a bantamweight, the tattooed 24-year-old seemed to have the MMA world at his feet.

"They sat me down," Garbrandt remembered, "and said, 'I truly believe you can be a star. It's gonna take a lot of hard work; it's not gonna be easy. But we believe you can do that.' So they've always had faith in me, from my performances. I knew what I was getting into. Maybe I wasn't ready for it on that scheme of things."

Two fights later, Garbrandt became the UFC bantamweight champion by beating longtime division bellwether Dominick Cruz. He was on the cusp of stardom.

But Garbrandt has not won since, a span of 1,254 days. He has lost three straight -- including two title fights -- as he goes into Saturday's co-main event with Raphael Assuncao. Injuries, illnesses (a staph infection that led to kidney issues) and recklessness inside the cage have led to an abrupt downturn.

"I literally went through every emotion in the past three years you can inside of a career," Garbrandt said. "From world champion to three-fight skid to injuries to hospitalizations. I never broke. I bent a little bit, but I never broke. You'll never see me give up. I kept driven and focused and knowing this is a long, hard road, a long, hard journey back to becoming a world champion."

Garbrandt said he's about to embark on "the biggest sports comeback ever." He's now training under coach Mark Henry in New Jersey, as well as his longtime Team Alpha Male gym in Sacramento, California. He believes he has made the corrections necessary to get back to the mountaintop. No fighter in UFC history has been a champion, lost three straight and then got the title back.

During his first UFC fight week, in 2015, Garbrandt slept with the UFC gloves when he first received them. He said this week he has had similar feelings -- and it's the most excited he has been for a fight since Cruz.

"That's how I know that young, hungry kid is back," Garbrandt said. "You take those little things for granted. ... It's fight week. I have not been excited for fight week in some time."

Bantamweights and more bantamweights are under the spotlight

Prior to the headlining women's fight, the men's bantamweight division takes center stage with two top-10 matchups. Just before the Garbrandt-Assuncao co-main event, there's a bout that could decide the next 135-pound title challenger: No. 3-ranked Aljamain Sterling vs. No. 6 Cory Sandhagen.

Sterling, in particular, is a beast on the ground. Here's a breakdown of his submission skills:

Undercard bits 'n' pieces: Five stats to know

1. Another bantamweight of note is undefeated Sean O'Malley, who returned from a 735-day layoff in March and stopped Jose Quinonez by first-round TKO. It was his seventh win by KO/TKO and seventh first-round finish. He's a -500 favorite over former WEC champ Eddie Wineland.

2. Neil Magny, who faces Anthony Rocco Martin, has 15 welterweight wins, tied for third most in division history. Magny is 14-1 in the UFC when landing a takedown, 1-5 when he doesn't. Martin has won five of his past six.

3. Chase Hooper is the first UFC fighter to compete on a pay-per-view card before his 21st birthday since Sage Northcutt in 2015. The unbeaten 20-year-old is looking to join Max Holloway as the only featherweights in UFC history to win multiple fights before turning 21. With a win over Alex Caceres, Hooper would be the first 145-pounder to start his UFC career 2-0 before age 21.

4. Gerald Meerschaert, who fights Ian Heinisch, has five submission wins, tied for the most by a middleweight in the UFC's modern era. All six of his UFC wins have come via stoppage; no UFC middleweight in the modern era has had his first seven UFC wins all come via stoppage. (Anderson Silva, Luke Rockhold and Jason MacDonald all did it in their first six wins.)

5. Brian Kelleher, who faces Cody Stamann at featherweight, will join Angela Hill as the only UFC fighters with three bouts in 2020, and he could become the first with three wins this year, which also would give him his first three-fight win streak in the UFC. Kelleher, an underdog in his past five UFC fights as well as in this one, is seeking to be only the fourth fighter in the past 10 years (along with Anthony Perosh, Ben Rothwell and Cub Swanson) to finish three straight opponents as an underdog.