By Ryan Burton

LAS VEGAS - In what is expected to be the final fight of his illustrious 19-year career, boxing superstar and pound-for-pound king Floyd "Money" Mayweather (48-0, 26 KOs) will put his undefeated record and WBC and WBA Welterweight World Championships on the line against power-punching, two-time welterweight world champion Andre Berto (30-3, 23 KOs) Saturday, Sept. 12 at the MGM Grand Garden Arena in Las Vegas, live on SHOWTIME PPV (8 p.m. ET/5 p.m. PT).

In what is expected to be the final fight of his illustrious 19-year career, boxing superstar and pound-for-pound king Floyd "Money" Mayweather (48-0, 26 KOs) will put his undefeated record and WBC and WBA Welterweight World Championships on the line against power-punching, two-time welterweight world champion Andre Berto (30-3, 23 KOs) Saturday, Sept. 12 at the MGM Grand Garden Arena in Las Vegas, live on SHOWTIME PPV (8 p.m. ET/5 p.m. PT).

Coming off of the Mayweather vs. Pacquiao event, in which Mayweather remained undefeated by taking a unanimous decision victory, Mayweather will test himself against a hard-hitting fighter hungry for his chance to score a historic upset. Mayweather could also make history. If triumphant, he would match the record of the late heavyweight champion Rocky Marciano, who retired in April 1956 with a record of 49-0. Equaling Marciano's record, one of the most hallowed in all of sports, would reaffirm Mayweather's legendary status in the sport and buttress Mayweather's claim as "The Best Ever."

Two stellar world championship fights will also be included on the pay-per-view telecast.

Roman "Rocky" Martinez (29-2-2, 17 KOs) will risk his WBO Junior Lightweight title in a rematch against the boxer he dethroned, four-time world champion Orlando "Siri" Salido (42-13-2, 29 KOs). Their first fight, in April of this year, is considered by many to be a leading candidate for Fight of the Year. In addition, Badou Jack "The Ripper" (19-1-1, 12 KOs) will make the first defense of his WBC Super Middleweight World title against mandatory challenger "Saint" George Groves (21-2, 16 KOs). A fourth fight on the pay-per-view telecast will be announced soon.

Promoted by Mayweather Promotions, the four-fight pay-per-view telecast will be produced and distributed live by SHOWTIME PPV and is the sixth and final fight of a record-breaking deal between Mayweather and Showtime Networks Inc. SHOWTIME Sports® will support the event with the Sports Emmy® Award-winning series ALL ACCESS.