McGregor's dismantling of Alvarez for the UFC lightweight title made him the first to hold two UFC titles simultaneously.
Mixed Martial Arts made an explosive entrance on the New York stage on Saturday with Irish superstar Conor McGregor's historic UFC 205 triumph at Madison Square Garden shattering revenue records.
McGregor's dismantling of Eddie Alvarez for the Ultimate Fighting Championship lightweight title made the UFC flyweight champ the first to hold two UFC titles simultaneously.
The historic result came in front of a packed house at one of America's most iconic sporting venues -- after eight years of legislative wrangling finally saw the state of New York lift its long-running ban of professional MMA in April.
Even before the doors of the lucrative New York market opened, UFC was a remarkable economic success, with an estimated turnover of $600 million in 2015.
This private MMA championship was bought in early July by the Beverly Hills-based sports marketing agency WME-IMG, for an estimated $4 billion. The success of Saturday's blockbuster card only enhances its value.
Some 20,427 spectators, $17.7 million in ticket sales and unprecedented pay-per-view sales pulverized all records, UFC president Dana White said at a press conference.
"The place was sold out, it was packed to the rafters," White said. "We broke the Madison Square Garden record, which I don't think will ever be broken again."
"Jesus is going to have to fight the devil to break that record," White crowed.
McGregor, beloved by fans not only for his prowess in the octagon but also for his swagger outside it, says he wants a bigger piece of the financial action.
"They need to come talk to me now," McGregor said. "No one's talked to me as a businessman since the sale's happened. That's not good.
"I mean, who owns the company now? People, celebrities, have shares in the company.
"Where's my share, where's my equity," added McGregor, who has never been shy about challenging White. "You want me to stick around, I want my share, I want my equity."
As predicted, the UFC at Madison Square Garden evoked the glamour of boxing's glory days. Gold chains and fur coats were in evidence along with a roster of star spectators that would be the envy of any New York sporting event.
Madonna, actor Hugh Jackman, singer Nick Jonas, new Spider-Man actor Tom Holland and singer Demi Lovato were among the vibrant crowd.
"It's completely different from other sports," says Michelle Knoll, whose sporting passions include the NHL's New York Rangers.
"I like that it's primal and animal, like cage fighting," she said.
UFC fighting takes place in the "octagon" an eight-sided cage nine meters in diameter.
The use of feet and fists is permitted, as well as ground combat, although the UFC has put in place strict rules to channel the violence in an attempt to avoid serious injuries.
The risk, however, remains present. Saturday's bout was halted as McGregor peppered his prone opponent's head with blows.
MMA is still banned in many countries, including France. Ireland's sports minister promised a crackdown on promoters in April after Portuguese fighter Joao Carvalho died from injuries received in a Total Extreme Fighting (TEF) MMA event in Dublin.
"It's not family entertainment," said Peter Downes, a 47-year-old from Ireland living in New York. "I have ten-year-olds and I would not take them to a UFC fight. When they're teenagers, maybe."
Knoll, admitting to some squeamishness at the "really, really bloody" moments, nevertheless said she found the atmosphere irresistible.
"There's that guy, dressed like a leprechaun," she said. "You don't see that at Rangers games."
There was a time when boxing turned heads in New York, with fans transported by Muhammad Ali, Joe Frazier or Roberto Duran.
Today, grumbled Jason Keney, "in boxing there can be five champions at the same time in the same category. It's ridiculous."
"They don't fight who they're meant to fight," added the 34-year-old, who traveled from Ireland for Saturday's card. "Here you get the best fights, you get the best people to fight each other."
In UFC, for "best" read McGregor and former judoka Ronda Rousey, twin deities of the circuit.
"He gets people excited," Downs said of the bearded, tattooed McGregor. "Because of his personality, his style. He's aggressive. He speaks his mind. There's no bullshit."
White, who has had his clashes with his outspoken star, also knows McGregor's value.
"Conor's special," he said. "I've never dealt with anybody like this kid on so many different levels."