Floyd Mayweather Jr. knew right away that he had Manny Pacquiao's number, as he boxed his way to a twelve round unanimous decision on Saturday night at the MGM Grand in Las Vegas.

Pacquiao's best round was the fourth when he landed with a hard southpaw left and for a moment the MGM Grand Garden Arena sensed an almighty upset was on the cards as he unleashed a barrage of blows, but Mayweather's survival instinct took over.

"He hit me with a solid shot. I can't say he's the toughest fighter or hardest puncher I've faced, but I can see why he has got where he has in boxing. I could counter and calculate all of his moves," Mayweather said.

"I knew I had him from round one. I thought I was beating him easily. He was applying pressure but wasn't landing any punches."

Only one outing is left on Mayweather's six-fight deal with Showtime and the Las Vegas resident is adamant he will retire once he has fought again in September, although he was reluctant to discuss any potential names for a contest that could see him equal Rocky Marciano's celebrated 49-0 record.

Even having the attention of the sporting world upon him has failed to rekindle his love for boxing, but he spoke at length about the 100 million dollar cheque handed to him by his promotional team after the fight and included the obligatory mentions of his Bugatti sports cars, private jet and mansions.

He also promised to hand back all of his world title belts on Monday to give other fighters their chance, saying nothing will be on the line when he steps into the ring for the final time in five months.

"It hasn't been two hours and you're trying to put me right back in a battle. Let me enjoy my victory. Can I enjoy my victory please?" he said.

"All I want to do is go home and rest and I'm not think about Manny Pacquiao this time.

"My love and passion for boxing is not what it once was, but this is my job and I have to do my best at it.

"This fight hasn't changed anything, it's just another day at work. It's no different to the guy I fought in my third fight....it's the same feeling.

"I'm not going to miss the sport. Before I wanted to be at every boxing event, but throughout the years I lost the love for the sport."