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If there's one thing that's heartbreaking about Khabib Nurmagomedov laying his gloves down in the center of the cage last Saturday at UFC 254 to signal the end of his 12-year pro career, it's that the UFC lightweight champion decided to walk away just as he was finding out how great he can be. 

Nurmagomedov, who improved to a gaudy 29-0, had just put the finishing touches on a dominant second-round submission of interim champion Justin Gaethje in Abu Dhabi. After an emotional reaction to his victory just three months following the death of his father and trainer, Nurmagomedov revealed a promise to his mother that he would never fight again without his father by his side. 

The news was certainly good for the deep ground of top contenders and future Hall of Famers that populate the 155-pound rankings below Nurmagomedov. But along with the time spent outside the cage due to bad luck and injury that limited Nurmagomedov to just seven UFC fights in the past six years, his early retirement comes at a point in which he raised the ceiling of his game to a level most never believed he would achieve. 

A fighter often labeled as one-dimensional due to his mastery of wrestling, Nurmagomedov evolved into an incredibly well-rounded force, particularly in the three fights that closed his career: title defenses against Conor McGregor, Dustin Poirier and Gaethje, with all three one-sided bouts ending via submission. 

What was evident so early in his fight with the dangerous Gaethje was how big the gap was between them from the standpoint of technique and execution. Nurmagomedov exhausted Gaethje early by constantly cutting off the cage to apply pressure. He also walked through heavy punches and hard leg kicks before swooping in to finish the fight with an incredible takedown and transition to full mount before applying a seated triangle choke. 

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For as historically deep as the lightweight division was during Nurmagomedov's reign as its best fighter, the fact that he was able to so impressively widen the gap between him and everyone else speaks best to how great he truly was. 

As a man of conviction as it pertains to his faith and the importance of his family, there's little reason to believe we ever will see him fight again. The decision to walk away while standing so firmly in possession of the title as pound-for-pound king should only help Nurmagomedov's legacy given the fact that we never saw him make a fatal mistake inside the cage or become badly compromised due to age, diminished skill or injury. 

Nurmagomedov will take his victory lap atop the P4P standings while the UFC decides what's next for the lightweight title. Whomever succeeds him over the next year as both 155-pound champion and the new king of the sport from a P4P standpoint, it's hard to imagine anyone being as dominant as "The Eagle."  

For CBS Sports' updated divisional rankings, click here.

Men's pound-for-pound rankings

Dropped out: Khabib Nurmagomedov

Just missed: Jan Blachowicz, Tony Ferguson, Robert Whittaker, Gilbert Burns, Brian Ortega, Aljamain Sterling, Conor McGregor

Women's pound-for-pound rankings

Dropped out: None

Just missed: Jessica Andrade, Germaine de Randamie, Tatiana Suarez, Holly Holm, Aspen Ladd, Yan Xiaonan