At flyweight level, 15-year-old Atichai Phoemsap was too strong for Armenia's Artur Bareyan, while in the light bantamweight division Asian Confederation Junior Boxing Championships bronze medallist Pluem Wangkhlaklang defeated Kristof Mislai of Hungary.

The country's third success was one of the biggest surprise results of the tournament so far, as Sakda Ruamtham eliminated Russia’s much-fancied Artem Bulatov at featherweight.

There were further surprises in the early rounds on day four with Ireland's Patrick Donovan performing well to defeat Kazakhstan’s decorated lightweight Abylay Ybraimov and Israel's Ricardas Tamulis out-pointing Azerbaijan’s Junior National Champion Huseyn Sadikhov in their light-bantamweight contest.

Elsewhere, Russia’s EUBC European Junior Champion Nikita Piskunov has now not lost for more than 14 months but he needed to be in fine form to beat Japan’s ASBC Asian Confederation Junior Boxing Championships gold medallist Ryutaro Nakagaki at light bantamweight.

Belarus’ Yukov Memorial Tournament gold medallist Artur Tuniyeu defeated Bulgarian Ivan Atanasov at featherweight, while Hungary’s Podgorica Junior Tournament winner Szilard Laszlo sent Moldovan light middleweight Maxim Neagu out of the tournament.

Erislandy Alvarez, who won the Cuban Junior National Games two months ago, continued his good run of form with victory over Russia’s Elzhan Eyniyev.

Their flyweight battle was seen as a meeting between two gold medal prospects.

The United States also had a good day as flyweight Rey Diaz, featherweight Gabriel Flores and light heavyweight Jared Anderson advanced to the quarter finals while lightweight Harley Mederos moved into round two.

The fifth competition day of the Championships tomorrow will be the longest at the event, with 72 bouts scheduled.