The most watched fight of all time

Boxers Floyd Mayweather Jr., left, and Manny Pacquiao pose with a WBC belt during a press conference Wednesday, April 29, 2015, in Las Vegas. Photo / AP.

The potential pay-per-view revenue for the Manny Pacquiao-Floyd Mayweather welterweight showdown is so stratospheric that with just four days to go before the fight, an actual figure is impossible to predict.

Stephen Espinoza, vice-president and general manager of Showtime Sports, said interest in the bout is unprecedented to a degree that the usual markers for predicting the number of purchases and revenue do not apply.

"Usually we get day by day updates of where the cable operators are in terms of their buys," Espinoza said.

"I can compare Wednesday to prior Wednesdays in prior pay-per-views.

"In general, that's fairly accurate. On this particular week, we're seeing numbers that have no precedent, so encouraging and so massive that you really can't extrapolate anything from them."

The fight which has been more than five years in the making between the top pound-for-pound fighters of their generation, will shatter the records for pay-per-view purchases.

It's just a question of how much more the fight will garner than the record 2.48 million pay-per-view purchases for Mayweather's 2007 fight with Oscar De La Hoya and the record pay-per-view revenue of US$150 million set by Mayweather v Saul "Canelo" Alvarez in 2013.

"Do we think it's a record-breaker? Absolutely," Espinoza said. "Whether that's 2.7 million buys or 3.2 I think both are possible but there's no way to choose one or the other right now."

Television revenue is just one of the financial records the fight is set to break.

Anticipated live gate receipts of some $70 million dwarf the previous record for a Nevada fight, the $20 million for Mayweather-Alvarez.

Regardless of the outcome, each fighter could make more than $100 million, with Mayweather saying this week he expects to pocket $200 million.

The pay-per-view revenue is also coming from a wider range of countries -- with 13 international pay-per-view territories.

"You'd have to go back to the Mike Tyson days to get near that figure," Espinoza said,

WHY THE MANNY PACQUIAO-FLOYD MAYWEATHER FIGHT IS THE BIGGEST EVER

* Highest revenue from live gate receipts

$20 million set by Floyd Mayweather-Saul Alvarez in 2013

Pacquiao-Mayweather projection: $70 million

* Most pay-per-view purchases

2.48 million for Floyd Mayweather-Oscar De La Hoya 2007

Pacquiao-Mayweather projection: Three million or more

* Highest pay-per-view revenue

$150 million for Mayweather-Alvarez in 2013

Pacquiao-Mayweather projection: $300 million in US, Puerto Rico and Canada alone

* Biggest purse

$70 million for Mayweather against Alvarez

Pacquiao-Mayweather projection: More than $100 million for both fighters

-AAP