By Ryan Burton

Floyd Mayweather equalled former heavyweight great Rocky Marciano's 49-0 record with a unanimous decision victory over Andre Berto before confirming his retirement.

Mayweather, who repeated his insistence in the build-up that this bout would be his last, was the heavy betting favourite and unsurprisingly dominated his overmatched foe to retain his WBC and WBA welterweight titles.

Scores of 120-108, 118-110 and 117-111 took the five-weight world champion, almost universally regarded as the best pound-for-pound fighter in the sport, to his 49th consecutive victory in the professional ranks.

Yet the 38-year-old seems to have no desire to reach a half-century as he said in his in-ring interview: "My career is over, that's official.

"You've got to know when to hang it up. I'm close to 40 now. There's nothing left to prove in the sport of boxing. Now I just want to spend time with my family.

"I'm leaving the sport with all my faculties; I'm still sharp and smart. I've accomplished everything in this sport, there's nothing else to accomplish."

He added: ";I don't want to rank myself, but I am the best at boxing."

Many pundits are sceptical of Mayweather, who has announced his intention to walk away from the sport in the past only to make a comeback, most notably returning to face Juan Manuel Marquez in July 2009 21 months after 'retiring' following his knockout of Ricky Hatton.