It was the start of a quest that had his parents drive him six hours round-trip from their San Diego home to his training in Los Angeles.

"He is one of the hardest working kids I ever saw," says Carl Borack of USA Fencing. "He is also a really gifted athlete and smart too. But I guess you would expect that from a Princeton boy."

That determination and intelligence helped take him to the quarter-finals of the men's individual epee competition on Tuesday where he slayed his own giant, surprising everyone by beating the world number two Alfredo Rota of Italy.

"He's been on the rise, he made eighth in the World Championships in Havana last year so we weren't too surprised to see him beat Rota. But it was still great for him and for the whole of U.S. fencing," said Borack.

But coming up against the defending champion Pavel Kolobkov of Russia, Thompson slipped to an honourable 15-11 defeat.

Kolobkov faces a tie against Lei Wang of China, ranked 27th in the world, who edged home 15-14 against the German Daniel Strigel.

American women Sada Jacobson and Mariel Zagunis reached the semi-finals of the women's individual sabre, and it was a good day for the Chinese as Xue Tan had earlier made her way through to the semi-finals of the women's individual sabre.

In another nail-biter, Eric Boisse won the battle of the French beating Fabrice Jeannet 15-14. He now takes on world number one Marcel Fischer of Switzerland in the semi-final, the Swiss having dispatched Silvio Fernandez of Venezuela 15-13.