"I'm already thinking about 2012," the 18-year-old Saunders said after Banteaux beat him 13-6 to advance to the quarter-finals.

Saunders, who had impressed in the first round by outboxing world championship bronze medallist Adem Kilicci of Turkey, struggled against a fast and clever opponent.

Banteaux, who had lost to Saunders on the countback earlier this year, took a 4-1 lead after the first round. Saunders fought his way back and trailed just 5-4 after the second round but the Cuban then took control.

"I'm a bit surprised with the score," said Saunders, a Romany living on a travellers' site on the outskirts of London whose great-grandfather was a bare-knuckle prize fighter in boxing booths around the showgrounds of England.

"The body blows were not scoring," Saunders added after failing in his bid to emulate compatriot Amir Khan, who was 17 when he won the lightweight silver medal in 2004 in Athens.

British coach Terry Edwards, who had already criticised the judging earlier in the tournament, said he, too, had found the scoring bizarre.

"I'm not sour grapes, Billy lost, but there were some inconsistencies in the scoring," he said.

Edwards, who guided Khan to his silver medal in Athens and super-heavyweight Audley Harrison to the gold in 2000 in Sydney, paid tribute to his fighter.

"Billy acted in a very mature, professional way," Edwards said. "He got beaten by the top act, the guy who will probably win the gold medal.

"I really hope Billy carries on until 2012," Edwards added. "His talent is exceptional. He is very mature for his age but he will be even more then and he will be able to deal with situations like the one he faced today. He's going to be awesome."