Iglesias, 32, had always seemed in control and in the second round he sent McCormack to the canvas. It was a blow from which the British fighter seemed never to recover.

The judges all had Iglesias ahead on their scorecards and gave a 5-0 verdict to the Cuban.

It was a second Olympic gold for Iglesias who had won nine years ago in London at light-welter and his third Olympic medal in all. He is only the fourth Cuban to achieve the feat.

"That puts me right up there and it shows how much I love the sport," Iglesias said.

"Many said it was the end of the line for me but only the boxers know what is really happening. We know the injuries that we suffer, what we have to suffer and what we have to overcome and what we need to move forward.

"I always knew that I had it in me. Now I think the doubters have been proven wrong and those who believed in me were right. I was always aware that I could achieve this."

World champion McCormack said: "I was up against a top fighter from Cuba. He’s an Olympic champion. I thought I’d won the first round but he just edged the second two.

"I have got no complaints. I lost to a very, very good fighter. It is what it is, I am ready for the pro ranks now."

Bronze went to Andrei Zamkovoi of the Russian Olympic Committee and Ireland’s Aidan Walsh was forced to retire from his semi-final with an ankle injury.

Earlier in the day Japan’s Sena Irie, known as the "Crocodile" had beaten world champion Nesthy Petecio by a unanimous verdict to win featherweight gold.

"It’s honourable for me to win the first gold medal for Japan in women’s boxing," Irie said.

"I’m not a talented athlete, I can’t even do a back-hip circle on the bar. I think I was able to show Japanese women that if we keep putting the work in, we can achieve something."

An emotional Petecio said: "It means a lot to me because I dedicate this fight aside from my family, for my country, for my best friend who died last February."

She paid tribute to her coach Nolito Velasco saying: "I’ve seen how hard he sacrificed a lot for this competition, so that’s why I’m emotional."

Bronze went to Britain’s Kariss Artingstall and Italy’s Irma Testa.