The "one-time-only" boxing match between a 40-year-old who retired two years ago and an Irishman making his pro debut in the sport is positioned to become the greatest-selling pay-per-view fight of all time.
Showtime executive vice president Stephen Espinoza said Friday "it's too early to declare a hard number" but Aug. 25's Floyd Mayweather Jr.-Conor McGregor fight is "tracking in the mid-to-high 4 million pay-per view buys."
"If we don't reach the record, we're going to be very, very close," he said, "we consider it a massive success."
"It was an exciting, entertaining fight and there was massive interest," Espinoza told The Times, crediting strong digital sales to boost the overall domestic take.
The bout is also expected to surpass the $600 million generated in total revenue by Mayweather's less-entertaining, unanimous-decision triumph over seven-division champion Manny Pacquiao, with final pay-per-view numbers expected by next week. The 2015 Mayweather-Pacquiao fight set a record with 4.6 million buys.
Mayweather passed Rocky Marciano to stand at 50-0 in a career that included world titles in five weight classes by scoring a 10th-round technical knockout of UFC fighter McGregor at T-Mobile Arena in Las Vegas.
By reverting to the type of animated street talk that propelled him to stardom as "Money" Mayweather, the veteran boxer and the fast-witted, two-division UFC champion McGregor engaged in a compelling verbal back-and-forth on four international tour stops to promote the fight.
That was preceded by more than a year of fervent discussion about the possibility of the novelty bout on social media, sports talk shows and newspapers.
Finally, the UFC, under the new ownership of WME/IMG's Ari Emanuel, opted to participate in its first-ever cross-promotion, bringing its powerful pay-per-view audience for this meeting pitting the most respected fighter in each combat sport.
Although McGregor, 29, had never officially participated in a pro boxing match, his striking skill in the UFC was the primary reason for his success, with knockouts or repeated knockdowns recorded against featherweight champion Jose Aldo, lightweight champion Eddie Alvarez and skilled MMA striker Nate Diaz.
And the fight provided some drama, as Mayweather intentionally did little in the first three rounds as McGregor landed some scoring blows and also expended energy that would cost him in the second half of the bout.
By batting Mayweather with some hammer fists atop the head and holding him a few times, McGregor brought some UFC flavor to the bout without any points being deducted by referee Robert Byrd.
By the sixth round, with Mayweather accurately banking on the prediction that McGregor would begin to gas out after 25 minutes (the longest possible UFC fight), the boxer began to land impressive punches on the Irishman.
The punishment increased in the ninth, with McGregor reduced to desperate holds to slow the abuse, and then an onslaught of punches in the 10th convinced Byrd to stop the fight.
UFC President Dana White spoke afterward as a man hurrying to keep his fighters penned in the UFC cage, but the success of Mayweather-McGregor gives fighters such as UFC champion Stipe Miocic a strong case to push for a showdown like the one he pressed for last weekend against heavyweight boxing champion Anthony Joshua.
The success of Mayweather-McGregor came even as HBO had a junior-middleweight title fight won by Puerto Rico's four-division champion Miguel Cotto competing for fight fans. Cotto's victory drew a peak audience of more than 800,000 viewers.