Top 5 MMA fighters of 2021

Another year has come and gone, and with that, tons of fights in the UFC, Bellator, and beyond.

Who made the biggest mark in 2021? Here's a look at theScore's five most successful MMA fighters of the year.

5. Max Holloway

Holloway found himself in a bit of a pickle in 2020. The former featherweight champion lost a second straight fight to reigning champ Alexander Volkanovski - never a good situation to be in. He needed to go above and beyond to earn another shot at getting his belt back.

So, that's exactly what he did.

Holloway turned in one of the best master classes in recent memory against Calvin Kattar to kick off his 2021 campaign. He obliterated Kattar in the striking department to win a unanimous decision in a fight that probably should've been stopped well before the final horn; UFC president Dana White was genuinely concerned about Kattar's safety in the later rounds.

Holloway returned toward the end of 2021 and faced another top contender in Yair Rodriguez. Holloway's performance wasn't nearly as dominant as it was against Kattar, but the two featherweights instead delivered a "Fight of the Year" candidate.

Holloway's two massive wins this year have left the UFC no choice but to book a trilogy fight with Volkanovski despite the fact Holloway has lost to him twice in the past two years.

4. Ciryl Gane

Gane was a man on a mission in 2021.

He started out the year on a bit of a slow note, picking up a lackluster win over Jairzinho Rozenstruik. But it was still a crucial triumph that moved Gane into the top five of the UFC heavyweight division.

He picked up the pace in his next bout, cruising past Alexander Volkov in a striking-filled affair four months later.

And then the big one: With the promotion opting to move forward with an interim heavyweight title because of a logistical disagreement with champion Francis Ngannou, Gane got the call to face off with Derrick Lewis.

"Bon Gamin" delivered his most impressive performance to date, outclassing Lewis on the feet before stopping him with strikes in the third round of his first UFC pay-per-view main event in August.

That set up a title unification bout with Ngannou, which is scheduled to headline UFC 270 in January. Gane, who's only been a pro MMA fighter since 2018, went from promising up-and-comer to serious threat to the undisputed title in the span of six months. That doesn't happen all the time.

3. Julianna Pena

Pena sneaked onto this list at the 11th hour, but she more than deserves the recognition.

Let's be real: This has nothing to do with Pena's January win over Sara McMann. This is 100% - no, 1,000% - because she did the unthinkable and slayed "The Lioness."

Pena talked a big game ahead of her women's bantamweight title bout with Amanda Nunes, the pound-for-pound queen at the time and clearly the greatest women's fighter of all time. She said Nunes was scared of her. She said she had the game plan to dethrone her. But people laughed off Pena's trash talk, and no one thought she could do it.

But then, on Dec. 11 in the co-main event of UFC 269, she did it. Pena submitted Nunes in the second round to become the new champion and record one of the biggest upsets in MMA history.

That was a career-altering victory for "The Venezuelan Vixen" - and, frankly, sport-altering, too. She deserves all the praise. Every last bit of it.

2. Charles Oliveira

Oliveira surged to contention in 2020. He proved he's the best lightweight on the planet in 2021.

On the heels of the biggest win of his career at the time against Tony Ferguson late last year, Oliveira rallied against Michael Chandler in May to knock him out in the second round. Oliveira claimed the vacant 155-pound title with the victory, filling in the hole left by former champ Khabib Nurmagomedov.

However, some still doubted whether Oliveira was indeed the best in the division. Many considered Dustin Poirier the No. 1 guy after Nurmagomedov retired, and Oliveira beating Chandler didn't change that. "Do Bronx" got a chance to prove those people wrong by defending his title against Poirier at UFC 269.

It was a back-and-forth fight, but Oliveira prevailed with a third-round submission. It's just about impossible to overstate how big of a win this was for Oliveira: Poirier was - and still is - a legitimate top-10 pound-for-pound talent in the UFC. The win moved Oliveira into the top five.

Plus, there's nothing you can take away from that victory. You can nitpick Oliveira's previous wins if you so choose: Ferguson seems to be at the tail end of his career, Kevin Lee is out of the UFC, and Chandler is a former Bellator champ who almost won. But with the Poirier submission - no, there's nothing you can say about this one. It was clean, and it was impressive.

One of the unlikeliest champions in UFC history, Oliveira is finally starting to get his due. No one, hopefully, is doubting him now.

1. Kamaru Usman

Talk about a lock for "Fighter of the Year."

A single calendar year can't get much better than what Usman managed to do in 2021: record three title defenses and ascend to the No. 1 position in the UFC pound-for-pound rankings.

These days, UFC champions tend to fight no more than twice a year. That's just how it goes. But the welterweight king apparently wanted to stay busier than most of his counterparts.

Usman started out 2021 with a TKO of former teammate Gilbert Burns, who was undefeated in the division at the time. Two months later, Usman scored a "Knockout of the Year" candidate in his rematch with Jorge Masvidal, ensuring that fans forgot about their lackluster first meeting in 2020.

"The Nigerian Nightmare" didn't stop there - it was time for another rematch to close out the year. He took on Colby Covington, who gave Usman his toughest fight to date in 2019. Their second bout was another competitive five-rounder, but Usman prevailed on the scorecards at UFC 268 in November to remain welterweight champ for the fifth time.

Between the Masvidal and Covington bouts, Usman rightfully moved up to the top spot on the men's pound-for-pound list, officially becoming king of the UFC. In addition to the folks on the UFC rankings panel, just about anyone who follows MMA will tell you he's currently the best fighter in the world. That's because of what he pulled off this year.

Burns, Masvidal, and Covington are three of the highest-ranked welterweights in the UFC not named Usman - that's a seriously impressive streak. If we're looking at pure name value, Usman has the best 2021 resume out of any fighter in the sport; to beat those guys in title fights as the defending champion makes it all the more impressive.

No one did 2021 better than Usman.

Honorable mentions: Rose Namajunas, Islam Makhachev, Valentina Shevchenko