That's the tale of the gambling market in the leadup to Sunday's super fight between UFC star McGregor and unbeaten boxer Mayweather in Las Vegas.
The two go at each other in a boxing contest, taking cocky Irishman McGregor out of his comfort zone.
ESPN Boxing has done the rounds of the Vegas sports betting agencies and come up with some interesting figures for what the punters think will unfold in a fight of such intrigue.
The biggest single bet is US$880,000 (NZ$1.2m) placed on Mayweather. Given that he is a firm favourite, there's a fair bit of risk in it with the net return for a victory being US$160,000 ($218,000).
Three other "low six-figure" bets on Mayweather have been reported.
The biggest single bet on McGregor is a US$75,000 (NZ$102,000) wager placed at the MGM casino where there has been plenty of money coming in for him. The MGM reports that as of Tuesday (US time), they would lose over US$2m (NZ$2.72m) if McGregor managed an upset victory.
Two major sports book operators in Las Vegas report that there have been 13 to 15 times more bets placed on McGregor than Mayweather as punters look to cash in on the upset odds.
The New Zealand TAB has Mayweather a firm favourite, paying $1.25 to McGregor's $3.70 in head-to-head betting.
A Mayweather knockout is the favoured decision at $1.70 followed by a Mayweather points decision at $3.40.
McGregor is paying $4.20 for the KO and $21 for a points decision.
Photo by: REUTERS Caption: Floyd Mayweather shadow boxes with weights at a Las Vegas training session