Josh Buatsi guaranteed Great Britain a boxing medal in Rio – and then revealed that Floyd Mayweather told him he will become a world champion.

The Croydon fighter, who had won his first two fights at the Games by knockout, defeated Algeria’s African champion Abdelhafid Benchabla on a unanimous points decision to reach the light-heavyweight semi-finals and secure at least a bronze medal.

Mayweather has been a spectator during the Rio boxing programme, and already had a chat with Buatsi.

“He said to me he had heard about me before I got here and that I was a great fighter, a future world champion,” Buatsi said. “It was good to hear that from someone like Mayweather, who I think is the greatest boxer of our generation.

“This month marks two years since I have been on the Great Britain team and international scene. I have been on a long winning streak and I want to keep it going. I want to dominate in every way I can. And 100 percent, I want more than bronze, and I will give it everything that I’ve got to make sure I get a gold.”

There was no joy for light-welterweight Pat McCormack, though, who lost on a split decision to Cuban Yasnier Toledo.

McCormack battled intensely throughout a classy fight, but the verdict did not go his way as he made a last-16 exit.

“I am absolutely gutted,” he said. “I got a terrible draw and never got the decision tonight. It is what it is. I know I can mix with the best. I only got beaten on a split decision by the number two seed.”

But Savannah Marshall made amends for her demoralising first-round exit at London 2012 to reach the women’s middleweight quarter-finals in Rio.

The Hartlepool boxer, though, claimed she had fought terribly in gaining a unanimous points victory over Sweden’s Anna Laurell, 11 years her senior.

“We all know what happened in London, and I was actually really nervous today,” said the 25-year-old. “I thought it was terrible. To be fair, I thought it was a lot closer than unanimous. I could hear the crowd shouting ‘Anna, Anna’ so I thought I must be down on points.”

Marshall was left stunned by her first-round defeat to Kazakhstan’s Marina Volnova four years ago, which came just three months after she had been crowned world champion on her 21st birthday.

She now meets Holland’s Nouchka Fontijn in her next Rio bout. Fontijn knocked Marshall out of this year’s World Championships at the semi-final stage in the second round.