By Gregory Stangrit

Former five division world champion Floyd Mayweather Jr. (49-0, 26KOs) spoke to a select group of journalists upon his arrival to Moscow, Russia.

Mayweather retired from the sport of boxing in September, following his twelve round decision victory over Andre Berto.

One of the questions thrown in his direction, Mayweather was asked to name the three toughest opponents of his near 20-year career.

On May 2nd, the Fight of The Century finally took place, when Mayweather collided with Manny Pacquiao. Mayweather won a twelve round unanimous decision. Their contest broke all sorts of financial records - including 4.6 million purchases on pay-per-view.

He says Pacquiao was a much better fighter than he expected.

"I can say that none of them were easy," said Mayweather. "Although I must say that Canelo was tough....Miguel Cotto [was tough]. Manny Pacquiao was very tough. Pacquiao is very good. He was better than I thought. "

Mayweather said he is very interested in opening a boxing school in Russia.

He plans to hold a training session on Friday, where 4,000 are expected to attend and the organizers are trying to break the Guiness record for the largest group training session for boxing.

Gregory Stangrit covers boxing for Allboxing.ru