Boxing: 'I thought I won' - Pacquiao

A devastated Manny Pacquiao insisted he believed he had beaten Floyd Mayweather despite judges awarding a unanimous points win to his opponent in the richest fight in history on Saturday.

Pacquiao, 36, said after the Las Vegas superfight he felt he had done enough to be awarded the decision against Mayweather, who cemented his place in the pantheon of boxing greats with a defensive masterclass.

"It was a good fight. I thought I won the fight. He didn't do nothing. He was always moving outside. I got him many times. I saw his punches," Pacquiao said.

But Pacquiao admitted he had struggled to connect with the elusive Mayweather.

"He was moving around too much, it wasn't easy throwing punches at him. If he would've stayed in one place, then I could have thrown punches," Pacquiao said.

"I was cutting him (off) and countering. I wanted to fight."

READ: Boxing: Mayweather beats Pacquiao by decision

Despite inferior height, reach and weight, Pacquiao was adamant that Mayweather's raw power had not troubled him.

"I was able to handle his power, he's not strong like previous opponents like (Antonio) Margarito," Pacquiao said.

"He's not bigger than me. It's not about the size. The size doesn't matter. I've fought guys bigger than him and had no problem," added Pacquiao, insisting he had not rallied late on because of a mistaken belief he was ahead.

"I thought I was up in the fight, so that's why I didn't attack harder in the 11th and 12th rounds," he said.