One day short of 12 months since his last bout, Mayweather, who also spent two months in jail in 2012 for a domestic abuse offence, landed an astonishing 60 percent of his power punches en route to a unanimous 12-round decision.
All three judges scored the fight 117-111 in favour of the undefeated Mayweather, who admitted that a damaged hand had prevented him from ending the fight early.
"I really was looking for a knockout, but I hurt my right hand," he revealed. "After that, I just had to box smart.
"Robert Guerrero was a tough warrior. He was trying to press the attack. But I got really good work in the gym and I felt comfortable in the ring. My defense was on point."
After an opening two rounds in which the southpaw Guerrero (31-2-1, 18 KOs) had some success, Mayweather (44-0, 26 KOs) seemed to slip into his comfort zone from the third.
Although the challenger's game plan seemed to be to back Mayweather to the ropes with his jab and then land punches to the body, the champion repeatedly slipped under his opponent's left, landed one or more right hands and moved out of danger.
After being hit with several rights in the third, Guerrero appeared more hesitant to commit to his attack, giving Mayweather yet more time to slip in and out of range and land his key punches.
"I thought Floyd did an excellent job tonight," said the 36-year-old's father and trainer Floyd Mayweather Sr.
"There was nothing he couldn't do in there tonight. I told him to steal it with the right hand. That was a punch (Guerrero) couldn't see and wasn't expecting each time he threw it."
By the eighth round, Mayweather was stepping up his assault, landing right hands with greater force and mixing in left hooks as he opened up a cut over a clearly hurt Guerrero's left eye.
At that stage, it appeared that Mayweather would stop Guerrero inside the distance and although he continued to paint his opponent with right hands and left hooks, the champion remained content to focus on coasting toward the finish.
"Floyd was tricky with his punches," Guerrero said in a post-fight interview. "He's a great fighter. He's slick and he's quick. He's better than I thought. He was definitely on his game tonight." — Reuters