It took a photo-finish to deny Nicola Sanders a gold medal at the World Championships, but in her first race since returning home from Japan with a silver medal, she was well beaten by the athlete who really is the world’s best in the 400 metres.

Sanya Richards missed out on the individual race in Osaka after finishing fourth in the United States trials. But she entered last night’s race as one of only two athletes still able to win the $1 million (about £500,000) jackpot for winning at all six Golden League meetings. Christine Ohuruogu, the British world champion, and Allyson Felix, the 21-year-old 200 metres world champion, both withdrew having been scheduled to appear, but it is doubtful that either could have lived with Richards.

With the American in the lane outside her, Sanders watched her rival streak away from the gun. After 200 metres, Sanders was 15 metres down and, while she clawed back some ground, she got nowhere near Richards, whose 49.29sec was the fastest in the world this year. Sanders was second in 50.34sec.

“I just wanted to keep in touch,” Sanders, who will again oppose Richards as she chases her jackpot in Berlin tomorrow, said. “Hopefully, I can run faster in Berlin but I’m happy with 50.34 — that would have been my PB before Osaka.”

Five days after breaking the 100 metres world record, Asafa Powell had only the clock to race against after the withdrawals of Tyson Gay and Derrick Atkins, who beat him into third place in Osaka, and won in 9.84sec — 0.1 slower than last Sunday’s time. Marlon Devonish was fourth in 10.16sec.

Yelena Isinbayeva is the other athlete still chasing her share of the $1 million bonus. The Russian needed only two jumps to win the pole vault.

Mo Farah finished sixth in the 5,000 metres in Osaka. Last night, he faced four of the five athletes who beat him in Japan and managed to turn the tables on one of them — Matt Tegenkamp, of the US. In front of him, though, were five Kenyans, three Ethiopians and a Ugandan. His time of 13min 7.00sec beat his personal best by 2.4sec, but was nearly 17 seconds behind the winner, Sileshi Sihine, of Ethiopia. Andy Baddeley was sixth in the 1,500 metres in 3min 34.74sec.

Meseret Defar, the Olympic and world 5,000 metres champion from Ethiopia, knocked nearly 12 seconds off her own world record for two miles as she set a mark of 8min 58.58sec.