LAS VEGAS, (Reuters) – Six-times world champion  Floyd Mayweather Jr. will put his unbeaten record on the line  when he faces fellow American Shane Mosley in a non-title  welterweight fight today.

Some of the biggest names in boxing have been speaking about the hotly anticipated bout scheduled for 12 rounds at the MGM Grand Garden Arena:

* Sugar Ray Leonard, one of the greatest boxers ever and seven-times world champion.

“I give the edge to Mayweather. How can I not based on his unblemished record? Mayweather is the man to beat and if there were any fighters that I thought had a chance to beat Floyd Mayweather, one would be Shane Mosley. An  intriguing fight.”

* Mexican Juan Manuel Marquez, five-times world champion who was comprehensively beaten by Mayweather in his most recent bout  in September. “This fight will be a real welterweight contest. Mosley can win if he is capable of closing Floyd’s exits and using his speed along with his power.”

* Filipino Manny Pacquiao, who enhanced his status as the best pound-for-pound fighter in the world with a commanding win over Miguel Cotto to claim the WBO welterweight title in  November.

“I’m for Shane Mosley… but he must do the right preparation. If he does, then he has a very good chance against Mayweather.”

* Britain’s undefeated world super-middleweight champion Joe Calzaghe, who retired from boxing in February 2009.

“I think it’s a 50-50 fight. It’s the most dangerous fight Mayweather has ever had. Mosley could upset him but I think it will be close.”

* Renowned trainer Angelo Dundee, who has worked with Muhammad Ali, Sugar Ray Leonard and George Foreman.

“Mayweather will have his toughest fight yet against Mosley, who came up the ranks and fought every tough Mexican. Mosley’s stronger and more  mature than anyone Mayweather has ever faced. While Mayweather is truly a one-of-a-kind fighter, I would have to give the edge  to Mosley by decision.”