Floyd Mayweather outclassed Carlos Baldomir to win the WBC welterweight title in Las Vegas before announcing he plans to retire after one more fight.
Mayweather has won titles at four different weights
Two of the three judges gave the 29-year-old Mayweather all 12 rounds, and the third awarded him 10.
"One more fight, then that's it for me," said an emotional Mayweather. "Every time I fight, it's blood, sweat, and tears because I love the sport."
The Michigan native could meet the legendary Oscar de la Hoya next year.
"I believe De la Hoya will want to fight me after tonight," said Mayweather, who cited wear and tear on his body and the desire to leave on top as the main reasons for his decision.
"If he wants to make the fight, he knows where to find me."
He was just too fast and I couldn't catch him, and when I did catch him I felt sluggish
Mayweather became a four-weight champion when he beat Zab Judah for the IBF version in April but gave it up in order to meet Baldomir.
He remains unbeaten after 37 professional contests, including 17 world title fights.
Baldomir, 35, was never floored by his opponent, who is widely accepted as being the best pound-for-pound fighter in the world.
But his face was bloodied from the first round on and he took punch after punch from his much faster and more skilled opponent.
The Argentine admitted he was unable to reproduce the form that had also seen him beat Zab Judah for the title and then Arturo Gatti in his one defence in July.
"He [Mayweather] was just too fast and I couldn't catch him, and when I did catch him I felt sluggish," said Baldomir.
The defeat could mean the end of Baldomir's career and he is set to make a decision on his future soon.
Meanwhile, Mexican Orlando Salido upset Robert Guerrero to win the IBF featherweight title by unanimous decision.