LAS VEGAS — Floyd Mayweather Jr. cemented his place among the pantheon of boxing greats with a unanimous decision over fellow American Andre Berto Saturday in what he has repeatedly said would be the final fight of his career. Mayweather, 38, easily outboxed his younger opponent over the 12 rounds to retain his WBC and WBA welterweight titles and improve his perfect career record to 49-0, matching the benchmark set by former heavyweight champion Rocky Marciano. Five-division world champion Mayweather dominated most of the exchanges in the MGM Grand Garden Arena with his lightning jabs, control of space and agile movement about the ring to finish well ahead on all three judges' scorecards. Berto, a 30-1 underdog against one of the best defensive fighters of all time, dropped to 30-4 as he suffered his fourth loss in his last seven fights. “Andre Berto has heart, a tremendous chin, he wouldn't lay down,” Mayweather said in a ringside interview after sinking to his knees after the final bell sounded before looking up at the rafters as the fans snapped pictures with their cell phones. Asked if he might be tempted to come back for a 50th fight, Mayweather replied: “My career is over. It's official. I'm financially secure and I'm in good health. “You've got to know when it's time to hang it up, so I think it's about time for me to hang it up. I'm close to 40 years old, I've been in this sport 19 years, been world champion for 18 years, I've broken all records. “There's nothing left to prove in the sport of boxing,” said Mayweather, who has made more than $700 million during his stellar career. Back in the ring for the first time since May when he beat Manny Pacquiao in a ‘mega-fight' that became the richest bout in boxing, Mayweather landed 232 of 410 punches thrown while Berto connected with just 83 of 495. Mayweather also dominated the jabs count, connecting with 83 of 191 compared to his opponent's paltry 39 of 301. However, it was a welterweight showdown that failed to capture the public's imagination given Berto's relatively low profile globally and his mixed run of results over the past four years, and it was low on entertainment value on the night. Barely five hours before the start, the MGM Grand box office said “a bunch of tickets” were still available for the arena in the price range between $300 and $1,500, and the official attendance ended up at 13,395 — 3,000 short of full capacity. Among those in the crowd were American actor, singer and comedian Jamie Foxx, Canadian pop star Justin Bieber and boxing Hall of Famers Evander Holyfield and Thomas Hearns. Jack retains title Badou Jack earned a split decision over George Groves to successfully defend his WBC super middleweight title at the first time of asking Saturday. The American-based Swede had the Englishman down in the first round, before Groves battled back to take an entertaining fight the full distance. Two judges scored it 115-112 and 116-111 to the champion, the third judge giving it to Groves, 114-113. Groves, 27, for whom it was a damaging third defeat in 25 fights, wasted no time in exiting the ring. Jack, who improved to 20-1-1 and was making the first defense of his belt, said: “He's a hell of a fighter. Charlo dethrones Bundrage Undefeated Jermall Charlo wrested the IBF junior middleweight title from 42-year-old Cornelius Bundrage Saturday, dethroning boxing's oldest current champion with dominating a third-round stoppage in Connecticut. The 25-year-old Charlo, who improved to 22-0, knocked Bundrage down four times before referee Johnny Callas put an end to the carnage at 2:33 of the third round. Bundrage (34-6, 19 KOs) failed to muster any kind of offence or keep the younger Charlo at bay. — Agencies