Chinese teenager Qiu Yike caused the biggest upset in recent history when he ousted the world number one Timo Boll of Germany in the second round of the men's singles at the world championships in Paris. Qiu, an 18-year-old from Sichuan province ranked only 40th in the world, came back from two games down to beat the 2002 World Cup winner 3-11, 7-11, 11-7, 14-12, 11-9, 12-10, turning the match upside down with a stunning comeback from 5-10 down in the sixth game. ' In the sixth set I thought, so what, there's still another game left. Since my opponent hadn't reached 11 points I thought I'd just give it a go,' said the teenager, who repaid the faith shown in him by a delighted head coach Cai Zhenhua. 'I was nervous in the beginning, but when I got to 2-2 I thought I would win. I've been practising critical situations like 8-9 or 9-9. I think that's been very helpful. It was a tough match and I think I have sprained my back a little.' Boll, meanwhile hinted the celebrity status he has gained in Germany since becoming world number one at the beginning of the year, played a part in his downfall. 'I probably haven't trained enough this year,' said the 22-year-old, who has been in demand with the German media since achieving his status. 'I have problems with my physical condition. I'm not as strong as I used to be. I wasn't as focused either.' However he denied he had been taken by surprise by the ability of Qiu, who is the reigning world under-21 champion. 'I didn't know him, but he's Chinese and he's playing at a World Championship. He had to be good. It's always fun to play against Chinese players, but it is never fun to lose to them.' However it was not all joy for China, simultaneously on a neighbouring table, World number six Li Nan bowed out of the women's singles, beaten 19-17 in a monumental struggle in the seventh game.