Mayweather (right) was rocked in round two but went on to dominate against Mosley
Floyd Mayweather scored a unanimous points win over fellow American Shane Mosley in their welterweight super-fight in Las Vegas on Saturday.
The 33-year-old recovered from almost being floored for the first time in his career in round two to win 11 of the 12 rounds and extend his record to 41-0.
The judges scored the bout 119-109, 119-109, 118-110 to Mayweather.
"I went toe-to-toe, it's not my style but I wanted to give (the fans) that kind of fight," he said afterwards.
Mosley may be five years older than his opponent but he took the bout to the five-weight champion in the early stages, and gained the initiative in round two.
Several big rights to the head saw Mayweather's legs buckle, and a follow-up flurry of body jabs forced him onto the ropes.
But the younger fighter regained control in rounds three and four with good combinations and body shots
In the fifth, Mayweather protected himself with a tight defence while continually landing rights and bloodying Mosley's nose.
Mosley was reprimanded for grabbing his opponent's arm in the eighth round, and Mayweather replied with a series of head shots and verbal taunts to his opponent.
Having been forced onto the back foot early on, the longer the bout went on, the more Mayweather dictated the pattern of the fight, as was reflected in the judges' scorecards.
"They wanted to see me moving, and coming forward and that's what I did," said Mayweather after the bout.
"We should have pressed the attack a lot earlier and we could have got the knockout, but Shane Mosley is a tough customer and he is one hell of a fighter."
Mayweather, who outclassed Mexican Juan Manuel Marquez in his most recent bout in September after a 21-month retirement, said the early scare had shaken him into action.
"That's all with the territory of boxing - only the strongest survive," he said.
"This is a contact sport, some time you are going to get hit with big shots, you must suck it up and keep fighting hard like a warrior."
If Manny Pacquiao will take the blood and urine tests, we can make the fight happen for all the fans
Mosley was left to rue his missed opportunity after having Mayweather on the ropes in the early stages.
"I caught him with my big right hand and I tried to move around but he was too quick and I was too tight," said the 38-year-old.
"After I landed the right hand, I thought I needed to knock him out but I needed to do it sooner than later. But I couldn't adjust and he did."
Mayweather was set to fight Philippine superstar Manny Pacquiao before a row over pre-fight blood-testing derailed negotiations, and insisted afterwards the match-up could still happen if Pacquiao agreed to the testing.
"If Manny Pacquiao wants to fight, it's not hard to find me," he said.
"If Manny Pacquiao will take the blood and urine tests, we can make the fight happen for all the fans."
Mosley, who has 46 wins from 52 fights and weighed in one pound heavier than Mayweather at 10st 7lbs, had not fought since a ninth-round stoppage of Antonio Margarito in January 2009.
His record now stands at 46 wins, six defeats and 39 knockouts.