Dana White felt lucky to see Khabib Nurmagomedov's final fight and will now give the retiring champion the time to "emotionally heal" before discussing the future.
Khabib beat Justin Gaethje at UFC 254 to unify the lightweight division, yet then revealed he had entered the Octagon for the final time.
The Russian, who lost his father and coach Abdulmanap Nurmagomedov to coronavirus complications, said he had promised his mother this would be his last bout.
UFC president White's post-event news conference prompted questions of whether he believed Khabib's claims.
White was not looking to place any pressure on the fighter, though, and also revealed "one of the toughest human beings on the planet" had been carrying a secret injury.
"What this guy's been through, we're all lucky that we got to see him fight tonight," White said.
"I'm hearing rumors of other things that I didn't hear about. Apparently he was in the hospital. He broke his foot three weeks ago.
"He has two broken toes and a bone in his foot that was broken – something like that – that's what his corner was telling me.
"He is one of the toughest human beings on the planet.
"He is the number one pound-for-pound fighter in the world. Seriously you have to start putting him up with GOAT status with whoever else you think is the GOAT.
"When guys want to fight, they want to fight. When guys don't want to fight, they don't want to fight.
"Let him take some time off, let him heal – not physically but emotionally heal from what he's going through with losing his father.
"As I said, we're all lucky we got to see him tonight."
White was blown away by Khabib's punishing performance, particularly after he struggled to make weight and appeared to be overcome with emotion before, during and after the event.
"It almost smelt like an upset tonight, the way he reacted at the weigh-in, the way he acted when he was walking out tonight," White said.
"He didn't look like himself, breathing heavy and taking deep breaths, but wow."