Few fighters have embodied the nominal title of people's champion more completely than Manny Pacquiao. It turns out he's also the people's choice at the sports books ahead of Saturday's high-profile showdown with Floyd Mayweather.

More than three-quarters of the bets placed at MGM Resorts sports books have been for Pacquiao, according to the man charged with overseeing betting lines on all events.

Jay Rood, vice president of race and sports books at MGM Resorts International, said the fight already represents the third-largest handle for a fight at that property.

“It will be either No2 or No1 by tomorrow afternoon,” Rood told the Guardian on Thursday. “It’s the biggest fight we’ve ever taken at the MGM Grand, and I think it will easily become the biggest fight in Nevada sports books in quite a while, if not ever.”

While the MGM doesn’t make public the specific numbers for its handle, Rood estimates the statewide figure to be “somewhere in the neighborhood of $20m to $25m” as of Thursday afternoon – an overwhelmingly positive bellwether given the majority of wagers typically come in the final two or three days.

“I think we’ll end up between $60m and $80m for this fight,” Rood said, which would surpass the record established by the September 2013 fight between Mayweather and Canelo Alvarez. By comparison, this year’s Super Bowl generated a handle of $116m, but that includes the vast menu of proposition bets far less conducive to boxing. Saturday’s fight is, however, expected to surpass what was wagered on the point spread.

Rood, who started as a ticket writer for one of MGM’s Lake Tahoe properties 20 years ago and today supervises the lines on all sporting events, attributes the astronomical numbers in part to attractive pricing for two wildly popular fighters. Mayweather is a -200 favorite after opening at -240, while Pacquiao is a +170 underdog after opening at +200.

“We’re getting big bets on both of them,” Rood said. “We got down to as low as -170 on Mayweather at one point, and that’s when most of the action started coming back on Mayweather and now we’re at two dollars. And we’ve been at [the current odds] for about a week now. We’re getting really good two-way action at that price.

“Mayweather hasn’t been this cheap since the De La Hoya fight (in 2007) and maybe only once or twice since he’s been a professional. And Manny Pacquiao is normally a pretty solid three-, four-, five-dollar favorite himself, so you’re getting plus money on him, which is great if you believe in Manny Pacquiao.”

Rood said the biggest wager to date has been a $500,000 bet on Pacquiao, though he’s been in communication with a punter seeking to place a $1m bet on Mayweather and hoped to have it finalized by Thursday night.

“We’ve been talking to them back and forth throughout the last three or four days,” he said. “It sounds like they’re getting their finances in order to get the bet in the cage.”

Rood, said tickets for Pacquiao are being written at a 3.3-1 ratio at the MGM, but the ratio at sports books further away from the strip are even more skewed toward the Filipino congressman, anywhere from 7-1 to 10-1.

“Public opinion is definitely Manny Pacquiao,” he said.

The trend makes Pacquiao by decision one of the biggest losing propositions for the MGM, but that would pale in comparison to a draw, which has been bet down to 6-1 after opening at 22-1.

“The draw is the landmine for us,” Rood said.

For an average fight, Rood will open the line on a draw at 30-1. He set it at 22-1 for the Saturday fight when betting opened on 20 Feburary in anticipation of some conspiracy-fueled action, but a flood of large wagers quickly forced his hand. He confessed the line for a draw “should be higher” but expects it to stay where it is: “My risk on it right now is so considerable that I’m not willing to risk my employment to offer a more legitimate price.”

Ultimately, it’s the crossover appeal of the fight of the century that will almost certainly elevate Mayweather-Pacquiao to record-breaking heights.

“I think there’s going to be a lot of people that maybe have never been to a boxing match and have never bet a boxing match,” he said. “They may be doing both this weekend and they may never do it again. This is definitely a once-in-a-lifetime event.”