Three smoky semifinals delivered three national records - yet only one of those was good enough to go through to Wednesday night's final, which looks like it could be an unexpected showdown between Novlene Williams, of Jamaica, and Britain's Nicola Sanders.
Williams won the first of three semi-finals (only the first two from each were guaranteed a place in the final) with a season's best 49.66 to go third on this year's rankings. In her bright yellow outfit, the 2005 silver medallist easily caught the eye of the good-sized crowd, and she was outstanding, too, in her running, coming off the final bend four metres ahead of her rivals. Former champion Ana Guevara, of Mexico, could only glance across the track in anxiety as she finished in 50.19, a season's best.
Ilona Usovich (50.31) and Joanne Cuddihy (50.73) set Belarus and Irish national records in finishing third and fourth, but would have to wait to see if they would progress as fast losers.
Sanders ran an equally positive race, to the obvious surprise of Russia's Natalya Antyukh, who spent the home straight gradually closing the Briton down, but still unable to quite catch her as they finished in a personal best 49.77 and 49.93, the fifth and seventh fastest times of the year. In third place, DeeDee Trotter, the American champion, would find that her 50.31 would progress as a fast loser.
Sanders was disqualified in the semi-final of the one-lap hurdles in Helsinki two years ago. Since then, she has reverted to flat racing with tremendous effect, winning the European Indoor title earlier this year with similar buccaneering tactics, although an injury delayed her seasonal debut this summer.
Sanders's team mate, Christine Ohuruogu also had a late start to her season, but seems to be finding form at just the right time. She showed little sign of race-rustiness or fatigue as she powered down the home straight to win the third semi-final in a personal best 50.16 ahead of Mary Wineberg (USA) in 50.27.
Osaka 2007 News Team/sd