UFC 239: Holly Holm in familiar territory as underdog spoiler ahead of Amanda Nunes bout

Holly Holm has already produced one earth-shattering upset in MMA when she knocked out Ronda Rousey nearly four years ago and she will need to repeat that spectacular feat if she is to dethrone 'Lioness' Amanda Nunes at UFC 239.

Going into her fight with Rousey in Australia in November 2015, Holly Holm was considered by most to be little more than an also-ran. Her opponent was undefeated at 10-0 and had won her previous four fights in a little over two minutes combined and had risen to the status of arguably the sport's biggest star at the time.

But then it all came crashing down. Holm, the former boxing world champion, overcame Rousey's early aggression to land a left high kick early in the second round which sent the champion tumbling to the canvas. It was a loss which would soon expedite Rousey's retirement from mixed martial arts and place Holm atop a division previously considered to be Rousey's exclusive playground.

On Saturday night in Las Vegas, Holly Holm has to do this all over again. Amanda Nunes, the UFC's 135 & 145lb champion, has a recent resume which contains the names of some of the sport's biggest names but none of them, not Valentina Shevchenko nor Cris Cyborg, or even Rousey herself, could adequately compete with the Brazilian slugger under her own terms.

Can Holm do any different? It will be a tough ask. The American is 2-4 in the octagon since her stunning win against Rousey in Melbourne, Australia. In the same span, Nunes has wracked off six straight victories - all but two of those by finish. 

And given her status as a two-division top dog in the UFC, Nunes says she has already cast her eye over the challenges posed by Holm.

"Well, she is not a champion anymore," Nunes said categorically to the media recently. "Of course she has holes in her game. Miesha Tate exposed her a lot. Valentina Shevchenko exposed her a lot. She has a bunch of fights even that she won that she have a lot of holes.

"I feel like I have to manage very well my time, and wait for the best moment. I don’t need to try and fight here, she has to come to me. She can run, she can try to outpoint me, but I am going to be sharp when I get her in the right moment."

It is a strategy which has paid serious dividends. Nunes has emerged from a crowded list (Rousey, Jedrzejczyk, Cyborg and others) to stand alone as the greatest female mixed martial artist in history, mostly owing to the concussive force she carries in her fists. 

Holm says that she is aware of the dangers she faces on Saturday but that she is more than equipped to deal with whatever comes her way.

"In order to have two belts in two different divisions, you have to be a special something," Holm said. "But she hasn’t faced Holly and that’s the bottom line.

"This is a whole different fight,” Holm continued. “Is she great? Yes. Am I up against a great fighter? Yeah. It wouldn’t be a big expectant title fight, she wouldn’t be where she’s at if she hadn’t done great things, so yes, it’s a very big fight but I’m ready for it I’ve been training my butt off and that’s what I’m doing. I’m working for a win.

"Every fighter has a different style and nobody is the same. I’m not Cyborg, I’m not Shevchenko, I’m Holly Holm."

The concept of upsets are built into the architecture of MMA to a far greater extent than in boxing, for example. Still, if Holly Holm is to reclaim UFC gold three years after she last held it, it would rank among any achievement by a mixed martial artist in recent years.

She has already done it once. Who can rule out a second?