LAS VEGAS – Floyd Mayweather showed yet again why he is, conclusively, the greatest fighter of his generation.

He brilliantly outboxed Robert Guerrero on Saturday at the MGM Grand Garden, cruising to a wide unanimous decision in their WBC welterweight title fight that probably would have been a stoppage had he not injured his right hand in the middle of the fight.

Mayweather is far beyond being judged against his peers, but the lack of depth and quality among them keeps him from seriously being regarded as one of the 10 best fighters ever.

[Related: Fans boo Floyd Mayweather's 'boring' style]

Sugar Ray Robinson is, without question, the greatest fighter who ever lived. He was 128-1-2 before he suffered his second defeat, and he beat enough Hall of Famers to fill a football team. Floyd Mayweather avoids a Robert Guerrero punch on Saturday. (USA Today)

The thing that Robinson, and more recent superstars such as Sugar Ray Leonard, Roberto Duran and Marvelous Marvin Hagler, had over Mayweather was elite opposition.

"Let me tell you this right here about the

LAS VEGAS – The countdown to the end of Floyd Mayweather Jr.'s legendary career began on Saturday with a brilliant performance in a victory over Robert Guerrero at the MGM Grand Garden.
Mayweather rolled his record to 44-0 and kept alive a dream to end his career with a perfect mark.

He signed a six-fight, 30-month contract with Showtime in February –  likely his final contract – and he started it off on the right foot.

Floyd Mayweather punches Robert Guerrero their WBC welterweight title fight. (USA Today)

He won a unanimous decision, with all three judges seeing it 117-111, to keep his WBC welterweight title.

Though Guerrero's trainer and father Ruben Guerrero shouted at the conclusion, "He ran like a chicken, baby," it was a masterful boxing performance by Mayweather.

Guerrero tried to pressure Mayweather, but Mayweather had none of it. Guerrero had some success pinning Mayweather in the corner in the first two rounds, but after that, Mayweather used his lateral movement and a laser accurate right hand to pummel Guerrero.

He landed more than 60 percent of his

LAS VEGAS – It's impossible to improve upon perfect, but when the subject is Floyd Mayweather Jr., the normal rules don't apply.

An outsider might say the 36-year-old boxer lives a perfect life. He's among the greatest ever to have competed in his sport. He owns a fleet of luxury cars, a massive and stylish home in a tony, golf-course community, wears hand-tailored custom suits and accentuates his wardrobe with more diamonds than Elizabeth Taylor could dream of having.

He employs a gaggle of assistants to take care of his every need, real or imagined. If he wants to go to the movies, he rents out the entire theater. He stays in the finest hotels and flies on a sleek private jet. Women throw themselves at him; men dream of being him.

It's some people's idea of a perfect life. In life, as in sport, however, perfection is very elusive.

And so, even with a 43-0 record, even with a spot among boxing's all-time greats long ago assured, even with every material thing he might want at his

(Warning: Video contains strong language so viewer discretion is advised.)

LAS VEGAS – It's hard to pinpoint when it first happened, perhaps late in 2009 or early in 2010. Robert Guerrero was an anonymous lightweight fighting even more anonymous opponents, yet, after nearly after bout, in almost every public appearance, his message was the same:

I want to fight Floyd Mayweather Jr. next.

Guerrero had the audacity to call out the best fighter in the world even though said fighter was competing several weight divisions above him. 

Few took Guerrero seriously and reporters struggled to change the topic to something more grounded when he'd bring up his desire to fight Mayweather. There was no point, the logic went, of talking and writing about a fight that was almost certainly never going to happen.

Guerrero and his team were nothing if not determined, though, and they never gave up hope. In late 2011, Guerrero's publicist solicited reporters' opinions about a potential Mayweather-Guerrero

(Warning: Video contains strong language so viewer discretion is advised.)

LAS VEGAS -- It was hardly the classiest tactic, but trainer Ruben Guerrero injected plenty of intrigue into his son Robert's upcoming welterweight title bout with Floyd Mayweather Jr. on Wednesday.

After a boring thank-you fest disguised as a news conference in the MGM Grand's Hollywood Theatre, promoter Oscar De La Hoya invited Ruben Guerrero to the dais to say a few words. Virtually every other speaker had gone on in a monotone fashion, thanking every entity possible, name-dropping sponsors ad nauseum and predicting a great fight.

Ruben Guerrero (R) calls Floyd Mayweather Jr. "a woman beater" as Robert Guerrero looks on (AP)Ruben Guerrero, who has been trying to steal the spotlight from his son by, among other things, challenging Mayweather's father to a fight, changed things quickly.

He ranted and raved like a madman, shouting about Mayweather's domestic violence conviction that forced the pound-for-pound top boxer to spend 57 days in a local jail last year.

He started slowly, alluding to his challenge to

LAS VEGAS – Floyd Mayweather, said Richard Schaefer on Tuesday as he looked across a large crowd that had gathered in the lobby of the MGM Grand specifically to catch a brief glimpse of the world's best boxer, is a details man.

The chief executive officer of Golden Boy Promotions, Schaefer said there are few details of a business deal that escape Mayweather's eagle-eyed scrutiny.

Floyd Mayweather Jr. is as focused on the business of boxing as he is on punching. (Getty Images)On this day, the people had crowded around a makeshift boxing ring erected in the lobby to help promote Mayweather's welterweight title fight Saturday in the Grand Garden Arena against Robert Guerrero. Many were snapping photos; a few carried signs in support of Mayweather. All were lively as they awaited his entrance.

A video board behind the front desk at the hotel included a scroll of a Twitter feed filled with comments about the fight. Trying to kill time to appease the crowd until the man they came to see had arrived, the day's host shouted into a microphone. Tickets, he said, were still available. The

UFC light heavyweight champion Jon Jones already has one loss and nearly suffered another Saturday, but no one has even come close to defeating him in the cage.

Despite his dominance of Chael Sonnen on Saturday at UFC 159 at the Prudential Center in Newark, N.J., Jones was only 27 seconds away from losing his belt. Jon Jones attends a press conference after UFC 159. (USA Today Sports)He suffered a broken toe while taking Sonnen down in the first round. Had referee Keith Peterson not stopped the bout at 4:33 as Jones was pounding on Sonnen, it is highly unlikely that the New Jersey commission would have allowed Jones to come out for the second round because of the gruesome injury. 

As a result, Jones would have lost the bout by knockout, even though a novice could see he was the far superior fighter.

Jones' one defeat came in a non-title bout in 2009 as a result of a highly controversial disqualification during a match with Matt "The Hammer" Hamill. Jones was disqualified for throwing an illegal elbow that caused Hamill to be injured. After reviewing a

LAS VEGAS – Floyd Mayweather Jr. was only about a year into his professional career and still a year away from fighting for his first world title when he was already considered by many boxing insiders as one of the game's elite talents.

Even while still a teenager, Mayweather had a preternatural ability to see an opponent's punches as well as deliver spectacularly fast and accurate counters.

He was an underdog when he met the great Genaro Hernandez for his first world title on Oct. 3, 1998, but only because Hernandez was so highly regarded and because so few could believe what they were seeing from Mayweather could be duplicated against an elite opponent. Floyd Mayweather Jr. lands a punch against Miguel Cotto. (AP)

Mayweather's rise to the top wasn't like that of Leon Spinks. Spinks became the heavyweight champion in his eighth professional bout through a set of good fortune and fluke circumstances.

Spinks was one of the gold medalists on the highly acclaimed 1976 U.S. Olympic team that got significant air time during ABC's television coverage