Tomorrow night Floyd Mayweather 40-0 (25) will take his first major exam fighting above lightweight when he meets WBA welterweight champion Shane Mosley 46-5 (39). For the past month Mayweather has performed brilliantly as boxings version of Rowdy Roddy Piper, portraying himself as the bad guy in trying to hype the PPV sales of the fight. Mayweather-Mosley isnt as anticipated or compelling as Leonard-Duran I, Leonard-Hearns I or De La Hoya-Trinidad, but it is one of the best fights that can be made in 2010 and its the biggest welterweight clash in over a decade. Its also the most important bout of Mayweathers career and one he cannot lose.

Although Mosley is/was a great fighter, hes crowding 39 and hasnt fought in sixteen months. Prior to that he wasnt considered to be anywhere near the top of his game. He resurrected his career perception based on his stoppage of Antonio Margarito in January of 2009 (a fight I picked him to lose). And thats not meant to deride Mosley. Shane will retire as one of the least appreciated great fighters in boxing history. However, his willingness to fight any and all of the best fighters of his era has him crossing paths with Mayweather at the wrong time. Instead of waiting for Mayweather to find the gumption to move up and face him at lightweight, Mosley moved up in weight and fought Oscar De La Hoya, Vernon Forrest and Winky Wright two times each. To anyone who believes Mayweather-Mosley wasnt realized seven or eight years ago because of Mosleys reluctance, youre so biased you cant see straight. One fighter went out of his way to meet the best fighters at a higher weight, and the other conveniently retired, saying there was nothing left to prove while Antonio Margarito, Miguel Cotto, Shane Mosley and Paul Williams were breathing down his neck in the division he held a title three years ago.

No one reading this doubts that Mayweather is one of the most skilled fighters of his era. But his undefeated record is somewhat hollow. Hes never agreed to a fight in which the deck wasnt stacked in his favor since his days fighting at lightweight – and that includes the upcoming Mosley bout.

Some fight observers question Mayweathers heart and toughness and imply that once hes dragged into a real firefight hell wilt and fold. Dont count me among that group. I happen to believe theres a fire breathing lion inside of Floyd Mayweather and if and when he loses, it wont be due to him backing down psychologically. I believe Mayweather will fight and rumble when hes pushed and a loss under those conditions will be the result of him succumbing to a stronger and better fighter, not a tougher or more determined one.

The Mayweather-Mosley clash has been discussed from every angle possible – including fighting styles and strategies, PEDs, drug testing and the relationship each fighter has with their father. Theres no need to continue that dialogue in this space.

This is what we know:

Floyd Mayweather was forced into taking this fight because he couldnt dictate the terms in solidifying a blockbuster bout with WBO welterweight champ Manny Pacquiao. Floyd also understands that he can save more face losing to Mosley (if he does) than if he lost to a former flyweight champ. He knows hes facing Mosley at an opportune time being Shane is on the decline at almost 39 years old and coming off the longest layoff of his career, coupled with some outside of the ring personal issues hanging over his head. Another thing Mayweather understands that Mosley doesnt even care about is, Floyd presents a style that troubles Shane, especially at this stage of his career, more-so than the opposite. Mosley is at his best when hes confronted by an opponent willing to bring the fight and engage him. He is more troubled with speed guys and movers when he has to push the fight – something hell be forced to do against Mayweather. Fighting above lightweight Mosley hasnt been very effective when hes had to implement a plan-B during the bout, something hell most likely have to do if hes to hand Mayweather his first career defeat.

This fight means everything to Mayweather because his legacy is on the line, thats irrefutable. On the other hand, Mosley already has the utmost respect of the boxing community and most historians. A loss to Mayweather at this stage of his career wont detract from the hall-of-fame career hes compiled. On the other hand Mayweather has conducted his career in a manner that hes not only insecure of his standing among the pantheon of all-time greats, hes to the point that if he loses to Mosley or perhaps Pacquiao down the road, hell be more remembered for the fight he lost than the forty or so he won. The bottom line is Mayweather will lose any hope of ever being considered one of the greats if he loses to Mosley eight years after Forrest beat him and three years after Cotto won a decision over him. In order for Mayweather to extend the conversation pertaining to his place among boxings greatest fighters, he must step up and seize the fight when he confronts Mosley. If hes half the fighter he insists he is, hell find a way to do it.

Hearing Floyd say that hes greater than Sugar Ray Robinson and Muhammad Ali has been amusing – being that Floyd doesnt believe that himself. The lie detector for all fighters boils down to the level of opposition they faced. Edwin Valero knocked out every opponent he fought on the way to earning two world titles – and no one considers him the greatest puncher in boxing history, no one. Mayweather may be undefeated but the names missing from his record define him as much or more than the ones on it.

However, just because Mayweathers record is in part due to brilliant match making, it doesnt mean he cant fight. So the question becomes how does one believe Floyd will perform versus an opponent who despite being rusty and on the decline, is still the most formidable and dangerous fighter hes ever confronted during his fourteen year professional career?

It says here that although Mayweather is somewhat overrated by many, he can fight. The timing couldnt be any better and the table is set perfectly for Floyd Mayweather to score the signature victory of his career over a version of Shane Mosley hes favored to beat.

In order for Mayweather to pass himself off as the great fighter he so desperately wants to be seen as he must be victorious against Mosley. Theres no way around it. The feeling here is Mayweather will win and that he appears to be on the cusp of fighting the most complete fight of his career against a still dangerous opponent. Beating Mosley would represent the defining moment of Mayweathers hall-of-fame career. But does beating him in 2010 really alter his standing among histories greatest fighters?

Frank Lotierzo can be contacted at