LAS VEGAS -- Conor McGregor vs. Chad Mendes might end up being the biggest fight of 2015 so far. But another McGregor bout would beat it out this year, if it goes down.

UFC president Dana White said he and CEO Lorenzo Fertitta have already talked about what they would do if McGregor beats Mendes in the UFC 189 main event Saturday at MGM Grand. McGregor would finally get to face Jose Aldo to unify the featherweight titles -- and the UFC would break the bank once again promoting it.

"If [McGregor] beats [Mendes], the Aldo fight is even bigger than it was this time," White said. "It's even bigger. And me and Lorenzo have already talked about it. We're gonna spend even more money than we did this time. We've gotta try to top the last commercial and all that sh*t."

The UFC spent the most it ever has promoting Aldo-McGregor, which was supposed to go down this weekend at UFC 189. But Aldo pulled out officially last week due to a rib injury and Mendes has stepped in. Aldo and McGregor were sent on an eight-city, five-country World Tour in March and April and the UFC spent the most it ever has on a commercial to promote the bout, which aired during the NBA Finals. Billboards and posters popped up all over major cities like New York, Los Angeles, Chicago and Boston.

Things are still at a fever pitch this weekend in Vegas, because of McGregor and the thousands of Irish fans that have taken over the city. But if it were Aldo vs. McGregor it would have been even crazier.

White has said the UFC is expecting a record gate of $7.1 million for UFC 189 and pay-per-view buys in the range of 1 million. If Aldo were healthy and fighting McGregor, those numbers could have risen. The weigh-ins Friday alone had more than 11,000 packing into MGM Grand. This week has been one of the greatest spectacles in UFC history.

"Obviously, two weeks before the fight, it sucks," White said. "But this thing is still rocking and rolling, man. We're lucky that Chad Mendes is a stud and stepped in on two weeks notice to take this fight and always stays in shape and was dying for this opportunity. So, we still have a great fight."

There's no telling what an Aldo-McGregor fight would do financially if McGregor beats Mendes on Saturday night. But that "if" still exists. McGregor still has many questions to answer as far as his actual skills in the Octagon and beating Mendes would quiet many doubters.

"Everybody in this room knows what a bad ass Mendes is and everybody has been saying Conor didn't fight a wrestler, Conor didn't [earn] his way to the top, da da da. [Mendes] is the No. 1-ranked guy in the world. He's only ever lost to Jose Aldo. He's got knockout power. He's probably one of the best wrestlers, it not the best wrestler, in the sport."