Undefeated welterweight Floyd Mayweather did all his hard work in the second half of the bout to overcome a stiff challenge from the fast-starting Marcos Maidana and unify two world titles in Las Vegas on Saturday.
At the end of 12 bruising rounds, American Mayweather (46-0, 26 KOs) was awarded a majority decision victory, adding the hard-hitting Argentine's World Boxing Association belt to his World Boxing Council title.
For the first few rounds, however, it looked as if Mayweather was in serious danger of losing his vaunted unbeaten record against a fighter launching a blizzard of punches and trapping the American against the ropes at every turn.
Eventually Mayweather was able to assert control, nullifying Maidana's assault and launching vicious counter-attacks of his own, picking up points with his jab as his opponent sought to bulldoze his way in close.
Mayweather exuded confidence while awaiting the decision, with one judge ruling the fight a 114-114 draw while the other two scored the bout 117-111 and 116-112 in his favour, but acknowledged he had been in a hard battle.
"I definitely feel like I won this fight. Floyd did not fight like a man, like I expected him to" - Marcos Maidana
"This was a tough, competitive fight, what the fans want to see," he told a post-fight interviewer in the ring.
"Normally I go out there, I box, I move. Finally, I was in a tough, competitive fight. He's a tough competitor and we gave the fans what they wanted to see."
Maidana (35-4, 31 KOs) began brightly, backing Mayweather to the ropes, landing clubbing punches from all angles and cutting the American above his right eye following an accidental clash of heads.
Supreme in defence, Mayweather was able to block many of his opponent's punches and launch short counters of his own but through four rounds, Maidana was out-working his more celebrated foe and ensuring the bout was fought on his own terms.
By round six, Mayweather was using his footwork to stay off the ropes and control the centre of the ring, where he launched powerful hooks and right crosses to Maidana's body and head.
Even as Mayweather took over, Maidana kept coming, continuing to throw punches even as his workrate and accuracy declined.
When the final bell sounded, he and many of those in the crowd at the MGM Grand Garden Arena felt he had done enough to get the decision.
"I definitely feel like I won this fight. Floyd did not fight like a man, like I expected him to," Maidana protested.
"He did win some rounds, but the majority of them I dominated. I did go after him, but he's a difficult fighter.
The victory sets Mayweather up for a possible contest against Britain's Amir Khan, who outpointed Luis Collazo on the undercard, although the American appeared willing to consider suggestions that Maidana had done enough to earn a second shot.
"If the fans want to see it again, we'll do it again," said Mayweather.
"I have to give him a rematch because I won the fight," responded Maidana. "I'm not scared of him. Why not give him the rematch?"
Any rematch would mean Amir Khan would have to wait longer for the Mayweather showdown he is intent on securing.
Khan took former world champion and veteran welterweight campaigner Collazo apart in his first bout in the 147lb division.
The Bolton fighter - whose last bout was in April 2013, when he struggled badly against the lightly regarded Julio Diaz - showed his class in Las Vegas by knocking down the rugged southpaw three times en route to a unanimous decision victory.
"People want to see a fight between me and Floyd," Khan said afterwards.
"Floyd hasn't seen speed. He's fighting people with explosive power. But styles make fights and I think my style will give him a lot of trouble.
"Floyd looks beatable. He's getting a little older now and that's why a lot of people want the fight now because they want a young lion to come up and they want to see him get beat. I think the only person who has the chance to do that is me."
However, the bout will definitely not happen in 2014 as Mayweather's next intended fight date in September is too close to the Muslim fasting period of Ramadan for Khan.