The Irishman lost his world title fight against his Russian rival two years ago when he submitted to a rear-naked choke in the fourth round in Las Vegas.
The aftermath proved most controversial when Khabib left the Octagon to clash with members of McGregor’s entourage landing him with a lengthy suspension.
McGregor had claimed earlier in the week that he believed he was winning the fight earlier in the contest but taking to social media on Thursday admitted to employing some illegal tactics.
“The knee into the eye socket was illegal yes, from this position, a beauty though,” he posted. “(A) never before seen shot, like many of my shots.
“I use the mount defence leg as a spring board, loading the knee below it, release and straight to the eye socket. Smashed it in!
“This strike should not be illegal, [it] should actually be enshrined! Look at him cower his head after it and keep it tucked, kept honest!
“[The] guy is latched onto my arm not letting go. Everything bar biting and gouging should be permitted here, are we fighting or what are we doing here?”
McGregor returned to the Octagon for the first time since that defeat earlier this year beating Donald Cerrone inside 40 seconds.
He is expected to face Dustin Poirier early next year with a rematch against Khabib or his opponent this weekend, Justin Gaethje, next on the agenda.