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No lead is ever truly safe in combat sports, a reality best evidenced by Leon Edwards' dramatic comeback victory over Kamaru Usman at UFC 278, when the welterweight title changed hands via fifth-round head kick knockout.  

Suddenly, it didn't matter how close Usman appeared to be toward his goal of equaling Anderson Silva's record of 16 consecutive UFC victories or whether he still had more work to do in the overall G.O.A.T. debate.  

The high kick heard 'round the world in Salt Lake City, Utah, was a cruel reminder of just how dangerous this sport can be, not to mention how many ways there are to lose a fight. But even more, the knockout provided Edwards, aptly nicknamed "Rocky," a chance at delivering one of the most inspirational moments the fight game has seen in recent memory.  

Often overlooked due to a perceived lack of marketing ability, the mild-mannered Edwards never allowed himself to quit despite how one-sided their rematch had become over the middle rounds. And the native of Jamaica, who fights out of England, finally cemented the pound-for-pound respect that has alluded him with the victory, extending his unbeaten streak since his first fight with Usman in 2015 to 11 bouts.  

While the result teases the idea that it may have been a fluke given how in control Usman was at the time behind his pressure style and grinding wrestling attack, the winning strike was anything but lucky. Edwards had studied Usman's mannerisms and ticks for a long time and deftly floated a straight jab that caused Usman to lean to his right just as Edwards uncorked the kick.

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Now, with his own unbeaten streak within the Octagon snapped at 15 fights, Usman may get the chance for immediate redemption in the form of a trilogy. Either way, "Rocky" not only shook up the world, he did the same to the list of the best fighters in the world.  

Using a criteria that takes into account everything from accomplishments to current form, let's take a closer look at the top fighters inside the Octagon.

For CBS Sports' updated divisional rankings, click here.

Men's pound-for-pound rankings

1. Alexander Volkanovski -- Featherweight champion (24-1)

Previous ranking: No. 1

With respect to Jose Aldo's 145-pound division record of seven title defenses, Volkanovski just took one step closer to featherweight G.O.A.T. status with his fourth. This wasn't just any title defense, however, as Volkanovski continued his evolution at 33 by leaving Max Holloway a bloody mess in their trilogy bout. The champ has teased a move up to lightweight to challenge Charles Oliveira for the title.

2. Israel Adesanya -- Middleweight champion (23-1)

Previous ranking: No. 3

Although he was unnecessarily booed during his UFC 276 title defense against Jared Cannonier, "The Last Stylebender" left the Octagon without a scratch after another dominant victory. Adesanya's next defense is expected to be a difficult one when former kickboxing rival Alex Pereira meets him on Nov. 12 in New York. 

3. Charles Oliveira -- Lightweight (33-8)

Previous ranking: No. 4

Although his 155-pound title is currently vacant after missing weight ahead of UFC 274, no one is disputing who the best active lightweight in the world is. Oliveira extended his win streak to 11 with a first-round submission of Justin Gaethje. Next up is the red-hot Islam Makhachev at UFC 280 in October. 

4. Kamaru Usman -- Welterweight (20-2)

Previous ranking: No. 2

Usman looked well and on his way to a sixth title defense and a tie with Anderson Silva for the record of most consecutive UFC wins until a miraculous head-kick knockout from Leon Edwards in Round 5 shocked the world at UFC 278. An immediate trilogy bout appears like the next move for the former champion who yielded the first takedown of his career in the opening round.  

5. Francis Ngannou -- Heavyweight champion (16-3)

Previous ranking: No. 5

Despite suffering a serious knee injury during training camp amid a very public contract battle with UFC brass, Ngannou gutted out a unification win against former teammate, and unbeaten interim champion, Ciryl Gane. Ngannou's UFC future remains in question as negotiations and injury recovery continue.

6. Aljamain Sterling -- Bantamweight champion (21-3)

Previous ranking: No. 6

For all the criticism aimed at Sterling in how he handled his disqualification victory over Petr Yan in their first meeting, "Aljo" was a completely different fighter in the rematch 13 months later. Sterling's split-decision victory at UFC 273 extended his win streak to seven overall and sets up an intriguing UFC 280 showdown with former champion TJ Dillashaw. 

7. Jiri Prochazka -- Light heavyweight champion (29-3-1)

Previous ranking: No. 7

It's time to give the unpredictable Prochazka his full due after extending his win streak to 13 in a dramatic and savage fifth-round submission of Glover Teixeira at UFC 275. Prochazka is 23-1-1 since 2013, avenging his lone defeat by knockout. He has also shown an elite chin and gas tank to package with his fight-ending power. 

8. Deiveson Figueiredo -- Flyweight champion (21-2-1)

Previous ranking: 8

Just how impressive was Figueiredo's win over Brandon Moreno in their trilogy fight? At 34, Figueiredo not only rebounded from a stoppage loss to regain his 125-pound title, he showed the kind of poise and patience under new coaches Henry Cejudo and Eric Albarracin he had been lacking. A fourth fight with Moreno, who just captured the interim crown, appears next.

9. Leon Edwards -- Welterweight champion (20-3, 1 NC)

Previous ranking: NR

A true life "Rocky" story played out in front of the eyes of MMA fans when the often overlooked Edwards rallied to stop Kamaru Usman in dramatic fashion at UFC 278. Edwards extended his unbeaten streak to 11 fights since his 2015 defeat to Usman and could be in line to return home to the U.K. for an instant trilogy fight.

10. Petr Yan -- Bantamweight (16-3)

Previous ranking: No. 9

It's hard to fault Yan's effort in coming up just short against Sterling in their long-awaited rematch. Although he called for an instant trilogy bout following his disputed decision loss, Yan chose to instead accept an October bout against Sean O'Malley in Abu Dhabi. 

Dropped out: Brandon Moreno

Just missed: Moreno, Max Holloway, Robert Whittaker, Dustin Poirier, TJ Dillashaw, Stipe Miocic 

Women's pound-for-pound rankings

1. Amanda Nunes -- Two-division champion (21-4)

Previous ranking: No. 2

Nunes soundly outpointed a stubborn Julianna Pena at UFC 277 to regain her 135-pound title and remind everyone of her G.O.A.T. ways. The victory was also a big one considering Nunes, after leaving American Top Team, started her own gym and changed her style.

2. Valentina Shevchenko -- Flyweight champion (23-3)

Previous ranking: No. 1

The combination of Nunes' comeback win and Shevchenko struggling in a disputed decision against Taila Santos dropped the 125-pound champion from the top spot. She may get a shot at leaving no doubt for good, however, should UFC move forward with a trilogy fight against Nunes at bantamweight.  

3. Rose Namajunas -- Strawweight (11-5)

Previous ranking: No. 3

A baffling strategy of defensive circling led to Namajunas surrendering her 115-pound title to inaugural champion Carla Esparza in their May rematch. Namajunas was barely touched in her unanimous decision loss. Still, the miscalculation was a huge one. 

4. Zhang Weili -- Strawweight (22-3) 

Previous ranking: No. 4

The former champion looked completely reborn following consecutive defeats to Namajunas when she sent Joanna Jedrzejczyk to retirement via vicious knockout in their UFC 275 rematch. A fresh shot at the belt is next for the native of China at UFC 281 in New York. 

5. Carla Esparza -- Strawweight champion (19-6)

Previous ranking: No. 5

Esparza simply took what was dealt to her and made the most of it by edging out Namajunas in their disappointing strawweight title rematch at UFC 274. Although the win won't do a ton for her critically, it will go a long way in adding to her resume as the now two-time champion extended her win streak to six. A November matchup against former champ Zhang Weili is next. 

Dropped out: None

Just missed: Jessica Andrade, Marina Rodriguez, Holly Holm, Talia Santos, Yan Xionan