Almaty (Kazakhstan), Oct 19 (IANS): Reigning Asian Champion Shiva Thapa (56kg) and reigning National Champion Thokchom Nanao Singh (49kg) marched into the pre-quarter finals of the AIBA World Boxing Championship here Saturday while Beijing Olympics bronze medallists Vijender Singh lost out in the round of 32.

Olympian and recently crowned Asian Champion Thapa produced a superb performance in his first bout of the championship.

He started slow against Mario Fernandez of the Philippines, but picked up pace in the second round.

Thapa went on to cement his place in the last 16 of the bantamweight division by virtue of a unanimous decision.

The Assamese boxer, who is seeded fourth in the tournament, will now take on Alberto Milan of Argentina in the next round.

Nanao, the first Indian boxer on the canvases in Almaty Saturday, was up against Aqeel Ahmed of Scotland. The Scottish boxer was taken by surprise with the aggressive approach adopted by Nanao.

The 22-year-old services boxer did not waste any time taking the attack to Ahmed. His lightening combinations coupled with his swift movement helped him gain a clear advantage.

He eased off the pedal in the last two rounds, but did enough to win the bout on a unanimous decision by the judges.

In the pre-quarter finals Monday, Nanao will lock horns with Anthony Rivera Chacon of Puerto Rico who is seeded eighth in the tournament.

But the Indian camp suffered a setback in the middleweight division. Vijender Singh, the 2009 World Cup bronze medal winner, was engaged in a close encounter with reigning European champion and fifth seed Jason Quigley of Ireland.

He landed some good punches on the Irish boxer, but in the end came up short -- a low blow warning in the final round did not help Vijender’s cause. In the end he lost on a split decision.