Britain's Steph Twell broke down in tears today after crashing out of the 1,500metres at the World Championships in Berlin.

The world junior champion felt unwell as she trailed home 12th in her heat in the Olympic Stadium in 4min 18.23sec, almost 15 seconds outside the personal best she set in Monaco on July 28.

"It's difficult to remember the race right now. I just did not feel right from the start," said Twell (below today). "I was working harder to fight for a place rather than having my own race. The laps went by without me realising and it was such an elbow fight. At the bell the group just went and I did not have the response that I normally do. I felt ready to race and being in the third heat was an advantage but I didn't feel myself. I felt unwell after the race, my stomach is not good at all."

Earlier Usain Bolt cruised through to the second round of the 200metres.

Bolt broke his own 100m world record in Berlin at the weekend with a stunning run of 9.58secs, taking 0.11sec off the mark he set in last year's Olympic final in Beijing.

But the Jamaican insisted he would put the partying on hold with the 200m heats and quarter-finals taking place today, and the 22-year-old looked suitably refreshed as he eased to victory in his heat in 20.70secs.

The task of winning the title has been made easier by the absence of defending champion Tyson Gay, who has a groin injury. Marlon Devonish, Britain's only representative after the withdrawals of Dwain Chambers and Toby Sandeman, also advanced after winning his heat in 20.92secs.