The Arroyo twins are the pride of Puerto Rico. McJoe got a bronze medal at bantamweight at the 2007 AIBA World Championships in Chicago. McWilliams, a fine flyweight, has just secured a medal for himself at the 2009 World Championships in Milan, but he is not content with the bronze.

Arroyo soundly beat top seed Yampier Hernández González of Cuba 6-2 in the first quarter-final of the evening session. "The secret of the victory is very simple," he said. "Two words: sacrifice, dedication. I have already beaten Hernández before, I was confident before the bout, I knew nobody works harder than me.

"The preparation for the World Championship was very long, six months, we have had many, many tournaments, among others in Cuba where I met Hernández as well. In my home country boxing is the No1 sport, and if I win the gold medal here - which is my goal - I will be a national hero."

Another Latin American talent, Óscar Valdez of Mexico, made the semi-finals on Wednesday evening in the 57kg category. The 18-year-old from Nogales gave a boxing clinic, beating his Armenian opponent Azat Hovhannisyan 14-9.

"It was tough, but not very tough," Valdez said beaming, accepting the handshake of his coach. "I started slowly, it was complicated in the beginning, but as time passed I felt stronger and stronger. I heard the roar of the crowd, I had the impression that not only the handful of Mexican fans, but also the Italian crowd supported me, which was very important for me. As I said earlier, I want to get the gold medal."

Gyula Káté of Hungary beat the 19-year-old prodigy from Kazakhstan Rustam Svayev. Káté dominated the whole nine minutes except for a few seconds in the third round when Svayev took the lead 8-7. But then the Kazakh was given a warning by the Argentinian referee, Káté suddenly connected with two beautiful right hooks and it was all over. Káté will meet the only medallist from the USA, Frankie Gomez, in the semi-finals on Friday.

At heavyweight Oleksandr Usyk of the Ukraine continued his cakewalk, this time against Vitalijus Subacijus of Lithuania with a 19-1 win. The young Ukrainian's combined score in his three bouts so far has been 46-4.