UFC 211 was a fantastic event, showcasing the full range of mixed martial arts to the causal and hardcore fan base, but the pay-per-view wasn't without its controversy.

Heavyweight champion Stipe Miocic defended his title in the main event, overwhelming and TKO'ing Junior dos Santos in the first round, and women's strawweight champ, Joanna Jędrzejczyk, defended her title for the fifth time against Jéssica Andrade, cruising to a unanimous decision win.

But most of the talk has come from the final preliminary bout between former lightweight title holder Eddie Alvarez and Dustin Poirier.

Alvarez, 33, landed several illegal knees in the second round to a grounded Poirier and the fight was ruled a no contest by veteran referee Herb Dean.

'The Underground King' was heavily rocked from a previous exchange with 'The Diamond' and Dean, who has refereed Alvarez in the past, declared that he was not looking to intentionally commit a foul against Poirier.

The rules state that the referee has the authority to issue a disqualification or no contest depending on whether he believes the fighter was intentionally breaking the rules or not. Dean used his judgement to discern that Alvarez, a former two-time Bellator lightweight champ with no history of foul play, intended to strike Poirier with knees but was not looking to consciously break the rules.

After the fight, Alvarez apologized but reaffirmed that he wasn't looking to cheat.

“I was in a fist fight,” Alvarez said, per MMA Fighting's Marc Raimondi. “I thought I had Dustin hurt and I thought he was a little tired. The first knee, I thought he was playing the game where he had his hand down. Herb (Dean) was very clear about you can’t play the game, so I hurt him with the first one, I think the second one may have been legal, but the third knee was illegal. I saw it on the prompter afterwards that it was illegal and I apologize to Dustin.”

Despite Alvarez' noble intentions, Poirier will be appealing the result to the the Texas Department of Licensing and Regulation (TLDR), per his manager, Robert Roverta, Ariel Helwani reports.

Part of the confusion lies in the recent rule change enforced by the Association of Boxing Commissions and Combative Sports (ABC) last year. The new Unified Rules of MMA state that it is now legal to knee an opponent that doesn't have both hands touching the ground, where as before, a fighter could not throw a knee to an opponent that had even one finger touching the mat. The Texas commission, however, has yet to adopt the new rule set.

Poirier, a top-ten lightweight and former featherweight contender, expressed his disappointment on Twitter and called for a rematch against Alvarez.

That was my fight... — The Diamond (@DustinPoirier) May 14, 2017