One of the best pound-for-pound boxers in the world, Mayweather (27-0, 20 KOs) captured the title with an eighth-round TKO of Genaro Hernandez in October 1998 and defended it nine times.
"I took my time. My game plan was to let him keep punching," Mayweather said. "He's not a hard puncher at all, he's a very busy fighter. A lot of amateur experience helped me. This is my last fight at 130 pounds, I can't make the weight anymore. I'm looking forward to moving up to 135."
Mayweather, 24, is widely considered one of the sport's purest boxers. He is expected to meet either IBF champion Paul Spadafora or WBC champion Jose Luis Castillo at 135 pounds and mentioned that he eventually would like to fight 140-pound champion Kostya Tszyu.
Coming off a 12-round decision over Carlos Hernandez in which he was bothered by hand problems, Mayweather used foot speed and overall ring awareness in the first three rounds as Chavez chased him.
Chavez (35-2) threw more than twice the punches Mayweather did in the first four rounds but was unable to hurt the champion. Mayweather began his offensive attack in the fifth and stunned Chavez with a few uppercuts in the sixth.
Mayweather continued to be the aggressor in the seventh and eighth rounds, when Chavez was visibly winded but showed a tough chin. After getting pounded in the ninth, Chavez took the advice of his corner and did not get off his stool for the 10th.