Only five people know what it's like to be in the ring with both Floyd Mayweather and Manny Pacquiao. A sixth name will be added to that exclusive list Saturday when Kenny Bayless becomes the first referee to step between the two boxers before the start of their welterweight world title fight at the MGM Grand Garden Arena.
Bayless is unlikely to get punched by either fighter but the other five — Oscar De La Hoya, Shane Mosley, Ricky Hatton, Juan Manuel Marquez and Miguel Cotto — were beaten up by both.
That, however, is where the similarities end.
"They're not the same," Mosley, who lost to both Mayweather and Pacquiao, said of Saturday's combatants. "One's more of a boxer, a mover and thinker."
That would be Mayweather.
"One's a hard puncher and a fighter."
That would be Pacquiao.
"Either one can win," Mosley said. "I don't think it's one-sided."
De La Hoya was boxing's biggest draw when he lost a split decision to Mayweather in 2007 in a bout that broke records for gate receipts, pay-per-view sales and revenue. Nineteen months later the Golden Boy lost to Pacquiao in a ninth-round TKO and never fought again.
In his first fight after beating De La Hoya, Mayweather met the unbeaten Hatton at 147 pounds and dominated the bout, winning in the eighth round on a TKO.
So Hatton went down to 140 pounds — where he still hadn't lost — for Pacquiao. But the result was even worse with Pacquiao knocking him down three times before the fight was stopped in the second round.
Hatton would fight just once more, also losing in a knockout.
Mosley fought Mayweather first and was a heavy underdog going into the 2010 fight, which the challenger nearly ended with a punishing right in the second round. Mayweather regrouped in the middle rounds to win a unanimous decision
A year later "Sugar Shane" was no contest for Pacquiao, who knocked Mosley down en route to a lopsided decision.
Cotto fought Pacquiao first and Pacquiao came into the 2009 fight riding a wave of momentum following wins over De La Hoya and Hatton. He dominated Cotto from the opening bell, sending him to the canvas in the third and fourth rounds before the fight was stopped in the 12th.
Two years later Cotto moved up to 154 pounds to meet Mayweather, who had to battle to win a unanimous decision.
Then there's Marquez, who met Pacquiao in four epic fights at four different weights between 2004 and 2012, knocking him out once, losing two decisions and battling to a draw.
There was little suspense, though, in his 2009 bout with Mayweather, who won a unanimous decision.
For Pacquiao to win, Mosley said, he'll have to be the aggressor. But that doesn't mean Mayweather will run. Mosley expects Mayweather to go toe-to-toe with Pacquiao at times, though he'll have to limit the length of those exchanges to avoid getting hurt.
"Pacquiao's got to throw some good shots, right hooks," Mosley said. "And I think that Mayweather would need to be smart, be strong."
No matter how it ends, both men will walk out of the ring much richer than they were when they climbed in.
Mayweather expects to earn more than $200 million for the fight while Pacquiao will get somewhere near $100 million.
Bayless, meanwhile, will make $25,000 for his historic night while the three judges who may wind up determining the winner — Dave Moretti of Las Vegas, Burt A. Clements of Reno and Glenn Feldman of Avon, Conn. — will get $20,000 each.
Times staff writer Lance Pugmire contributed to this report.