Dana White said UFC 251 was "trending off the charts" and was comparable to Conor McGregor's fight with Khabib Nurmagomedov.
Headlined by Kamaru Usman's welterweight title fight against Jorge Masvidal, UFC 251 – to be held in Abu Dhabi on Sunday – will see three title bouts.
UFC president White said the only event that compared was Khabib's win over McGregor in Las Vegas in 2018.
"This thing is trending off the charts. This thing is trending higher than a Conor McGregor fight," he told reporters.
"The only thing that this fight is comparable to is Conor-Khabib."
White added: "This thing is trending as big as a fight as I've ever seen in my entire career."
FOR WELTERWEIGHT GOLD.
— UFC (@ufc) July 10, 2020
@USMAN84kg vs @GamebredFighter
Order now https://t.co/bzG8eulB7q #UFC251 pic.twitter.com/VObQcd0mrp
Masvidal will fight for the title on six days notice, replacing Gilbert Burns after the Brazilian tested positive for coronavirus.
Despite the short notice, Masvidal (35-13) insisted he was ready to go against Usman (16-1).
"I had six days notice, how prepared could I be? I'm just as prepared as I need to be for Usman, but it's not like a full training camp, it's not like I've had six months to prepare," he said.
"That would be different, my weight wouldn't have been as high so I'm not going to say weight-wise my weight is 100 per cent.
"But everything else, my mind is ready, my skill set is better than him on any day of the week so I just get to go out there and prove it."