McGregor was choked out by bitter rival Nurmagomedov at UFC 229 back in October 2018 but says he would have won the next meeting had they clashed again.
Undefeated lightweight champion Nurmagomedov called it quits recently after beating Justin Gaethje at UFC 254, vowing to keep a promise to his mother that it would be his last fight.
But, in a Twitter Q&A, McGregor implied there was another reason why the Dagestani star had decided to hang up his gloves.
"A phenomenal grappler fighter," said McGregor.
"The current best in the sport with it. I've the answer, however, and they know it."
Nurmagomedov's second-round win over Gaethje in Abu Dhabi extended his record to 29-0.
He had been expected to continue fighting, but confirmed his mother had asked him not to carry on competing without his father Abdulmanap, who passed away earlier this year due to complications caused by Covid-19.
A phenomenal grappler fighter. The current best in the sport with it.
I've the answer however and they know it.
Congrats on the plumbing apprenticeship and thank you for the well wishes!
Same to you and yours :pray: https://t.co/AUCYizMjRk
- Conor McGregor (@TheNotoriousMMA) November 1, 2020
However, UFC president Dana White expects his champion to return to the octagon.
He said: "He was super emotional after that fight and you know he got the measles, the mumps, whatever he got.
"Then he broke his toe leading into that fight, took the fight, and with the passing of his father I just think he was super emotional and was just in the moment that night.
"I am not saying that he is going to 100% come out for 30-0, but I get the feeling that he will."
McGregor, meanwhile, predicted he will be a billionaire in just three years and named his toughest ever UFC opponent during his Twitter chat.
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