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After a multi-month promotional build-up that included a 10-city tour, a four-part documentary and countless heady estimates of potential pay-per-view revenue, the anticipated fight between Floyd Mayweather Jr. and young pound-for-pound challenger Saul Alvarez is hours away.

The two men will meet Saturday night at the MGM Grand in Las Vegas, in front of a live gate that Golden Boy Promotions executive Richard Schaefer said has exceeded $20 million and expectations of a challenge to the six-year-old PPV record of 2.4 million buys.

That record was established by Mayweather and promoter Oscar De La Hoya when they met -- a fight Mayweather won by split decision -- and De La Hoya has told anyone who'd listen that the 23-year-old Alvarez has the right stuff to be the first to topple the brash five-division champion.

Not surprisingly, Mayweather, now 36 years old, disagrees.

"If the game plan is to keep pressure, I can handle it," he said. "If the game plan is to outbox me, nobody can outbox me. You have to be able to outmatch me mentally, and I'm the strongest mental fighter in the sport of boxing."

The fight is being contested for the WBA and WBC titles at 154 pounds, one of which is held by each man. Mayweather won the WBA belt from Miguel Cotto in 2012 and is 21-0 in world title fights over five weight classes in a 17-year career. Alvarez won the WBC crown in 2011 and has defended six times, running his career title-fight record to 7-0 and his overall mark to 42-0-1.

While the official weight limit for the super welterweight division is 154, the fight will be contested at a 152-pound "catchweight" thanks to a contractual agreement made by the two camps. Alvarez hasn't weighed 152 or less for a fight since 2011, while Mayweather has fought above 147 just twice -- for the De La Hoya and Cotto wins.

The Showtime pay-per-view broadcast on fight night will begin at 9 p.m. ET and will feature three other fights -- including two for world titles -- before the main event.

Because he stands an inch taller and is broader through the chest and shoulders, Alvarez is considered the stronger of the two fighters and is expected to press the action while trying to bully Mayweather.

Mayweather, meanwhile, has long relied on sublime defensive abilities and quick, precise punching to combat aggressive opponents. In his most recent fight, in Las Vegas in May, he won nine rounds on all three scorecards while defeating Robert Guerrero, who entered that fight with the consensus nod as the stronger, more powerful man.

WBC president Jose Sulaiman, while appearing at the fight's media tour stop in Mexico City, put Mayweather on a particularly high pedestal when it came to all-time standing.

"I believe without a doubt he is one of the top 15 fighters in boxing history," he said. "And I definitely think this is the most important fight for Mexico in many years, as well as for the WBC. Mayweather is without question the best pound-for-pound fighter, and Alvarez is very valiant and will give everything that he has."

In his most recent fight, against previously unbeaten Austin Trout, Alvarez struggled early against a more skilled boxer before wearing Trout down with body work and powerful single shots. He scored a knockdown with a straight right hand in the seventh round and ultimately winning seven, nine and 11 rounds on the three scorecards -- though many observers had it scored a bit closer.

Mayweather's stamina and an ability to adjust in the midst of fights has long been celebrated, but the Alvarez fight will mark the first time he's fought twice in a calendar year since 2007 and the shortest turnaround between bouts -- four months, 10 days -- since he fought Diego Corrales and Carlos Hernandez within four months and six days in 2001.

His trainer and father, Floyd Mayweather Sr., claims the faster return to the ring will be a benefit.

"He'll definitely be sharper because of it," he said. "If you get up and walk down the block one day, then you'll go back the next day and walk a little father. Eventually, you'll start jogging, and then all of a sudden you're running a long distance. It's no different with my son. Being in the ring more often will guarantee he stays sharp."

Oddsmakers have installed Mayweather as a comfortable, albeit not prohibitive favorite. It would take a $280 wager on him to recoup $100 at sports.bovada.lv, while a $100 outlay on Alvarez would return $220 in the event of an upset.

FIGHT CAPSULE

WBA/WBC super welterweight titles - Las Vegas, Nev.

Floyd Mayweather Jr. (WBA champion) vs. Saul Alvarez (WBC champion)

Mayweather (44-0, 26 KO): First title defense; Twenty-second title fight in five divisions (21-0)

Alvarez (42-0-1, 30 KO): Seventh title defense; Third fight in Las Vegas (2-0)

Prediction: "Alvarez is a younger, bigger and stronger edition of the guy who's been groomed to defeat Mayweather for years, but has always failed. The result doesn't change here." Mayweather in 10

Lyle Fitzsimmons is a veteran sports columnist who's written professionally since 1988 and covered boxing since 1995. His work is published in print and posted online for clients in North America and Europe. Reach him at fitzbitz@msn.com or follow him on Twitter: @fitzbitz.