Demetrious Johnson was reminded of this fact in the worst possible way when Adriano Moraes nailed him with a knee strike to the head while he was downed, leading to Mighty Mouse's first stoppage loss ever.
In the UFC, hitting a downed fighter is illegal. However, some fighters, fans and critics have been pushing for a rule change that would allow UFC fighters to throw knee strikes at a downed opponent. Ironically, Johnson is at the forefront of this movement.
If Mighty Mouse and the rest got their wish and the UFC unbanned the knee strike to a downed fighter, the Octagon would be a very different place. Such a rule change could improve the games of some fighters who are already elite as is.
On that note, let's explore five fighters who would greatly benefit from the implementation of ONE Championship's rules on grounded knees in the UFC.
#5 Petr Yan
The most recent disqualification in the Octagon occurred during Petr Yan's title defense against Aljamain Sterling. Yan was seemingly moments away from retaining his title as he led in two of the judges' scorecards in the fourth round.
Petr Yan, however, landed an illegal knee strike to the grounded Aljamain Sterling with under a minute remaining in round four. The move led to Yan's disqualification and Sterling's coronation as the new UFC bantamweight champion.
An argument can be made that Petr Yan would have benefitted the most if grounded knee strikes were allowed in the Octagon. After all, he still might be champion today if it wasn't for a momentary lapse of judgment.
#4 Khabib Nurmagomedov
To be clear, Khabib Nurmagomedov didn't need a grounded knee strike to steamroll every fighter he faced in the Octagon. However, having that option could have made Khabib Nurmagomedov an even deadlier fighter.
In round two of his title defense against Conor McGregor, Khabib had the Irishman in a position where he could have scored a stoppage with a grounded knee strike. However, Conor McGregor was able to get back to his feet because Khabib Nurmagomedov wasn't allowed to throw knees at his head while he was downed. It didn't matter in the end as Khabib gave McGregor a merciless beatdown before choking him out in the fourth round.
Khabib Nurmagomedov's game plan for every opponent had always been predictable but it didn't make a difference as no one had the ability to stop him anyway. If he had been allowed to knee an opponent who was trying to get up, Khabib Nurmagomedov would have had an easier time in the Octagon.
#3 Israel Adesanya
Israel Adesanya's bread and butter is his stand-up game. At UFC 259, Jan Blachowicz knew that and exploited Adesanya's deficient ground game. Blachowicz scored some timely takedowns late in the fight that led to a successful defense of his UFC light heavyweight title.
Israel Adesanya's lack of a complete overall game is exactly why he would benefit from easing the restrictions on the striking department. By unbanning grounded knee strikes, Israel Adesanya would get another weapon which he could use to put his opponents away.
#2 Colby Covington
Colby Covington has recently been on a tear, having won eight out of his last nine fights. His success in the cage is largely due to his inhuman-like endurance, which allows him to throw a massive volume of strikes mixed up with some wrestling-based offense.
However, the biggest criticism of Colby Covington's game is his inability to finish most of his opponents. On top of that, his methodical approach often results in lopsided wins that many fans deem unexciting.
Unbanning the grounded knee strike could be a welcome change for Colby Covington. According to a Discovery Channel documentary about martial arts, the knee strike is the single most powerful weapon in combat sports.
If Colby Covington could pair his world-class wrestling skills with a diet of grounded knee strikes, his finish rate in the UFC could drastically increase.
#1 Jon Jones
Jon Jones has been one of the most dominant fighters in UFC history. Over the course of his UFC tenure, Jon Jones has relied on his phenomenal wrestling skills and ground game to put away most of his opponents.
As of late, there have been faint signs of slippage in Jon Jones's game with his three most recent fights going to the hands of the judges. Making the grounded knee strike available to Jon Jones could potentially add another dimension to his diverse offensive arsenal. An extra weapon would come in handy for Bones as he approaches the twilight of his prime.
On top of that, Jon Jones's only defeat in the Octagon was a disqualification due to illegal elbow strikes. Safe to say, Jones would very much be in favor of unbanning moves that are deemed illegal by the UFC.