Mayweather extended his unbeaten record to 44-0 with a unanimous 117-111 points victory over Guerrero, and the 'Ghost' said that he had not anticipated his opponent's superiority.
Speaking after the fight, the welterweight told reporters: "He's better than I thought but I would like to fight him again before he retires.
"This wasn't my night to beat him. He's slick and he's quick and he hit me with some good shots."
The loss was the second of Guerrero's professional career.