Argentina's Marcos Maidana came close to one of the bigger upsets in recent boxing history as he took the fight right up to Floyd Mayweather for 12 tough rounds, before losing a majority decision.
Mayweather, regarded as the world's best fighter pound-for-pound, retained his unbeaten record, but not by much.
Maidana swarmed all over him from the opening bell and gave him perhaps his toughest fight in a 16-year professional career.
He wasn't that tough, I thought I won.
In the end, though, Mayweather retained his WBC welterweight title by winning 117-111 on one scorecard and 116-112 on another. A third judge had it even at 114-114.
Maidana threw far more punches, but Mayweather was more accurate as the two battled into the late rounds with the fight still very much in doubt.
Cheered on by a large contingent of Argentine fans, Maidana took the fight to Mayweather, who was cut by the right eye in the fourth round by an accidental head butt.
"It was a tough, competitive fight," Mayweather said. "I normally like to go out there and box and move. But he put pressure on me. I wanted to give the fans what they wanted to see so I stood and fought him."
Maidana raised his arms in victory when the final bell sounded, and Mayweather watched pensively from his corner as the scorecards were added up before he was declared the winner.
"He never hurt me with a punch," Maidana said. "He wasn't that tough, I thought I won."
Maidana had said before the fight he was going to treat Mayweather like any other fighter and go right after him.
Big money Mayweather
He did just that, bringing the sellout crowd at the MGM Grand hotel in Las Vegas to its feet as he landed some big overhand right hands to the top of Mayweather's head.
Mayweather, who earned $32 million for the fight, was a 6-1 favorite coming to remain unbeaten. He had picked Maidana over Amir Khan as an opponent and may have been ruing that decision.
Maidana, who was cheered by the crowd as he left the ring, said he wanted a rematch, and both promoter Richard Schaefer and Mayweather said he just might get one after nearly pulling off one of the biggest upsets in recent years.