South Africa's Caster Semenya has lost the 800m world title she won in Berlin two years ago, claiming silver behind Russian Mariya Savinova.
The 20-year-old, whose career has been shrouded in controversy because of doubts over her gender, moved to the front on the home straight but Savinova pipped her on the line to take gold, winning in a time of 1.55.87.
Semenya - banned from running for much of the first year of her reign as world champion while an IAAF investigation into her gender was conducted - ran in 1.56.35, her best time of the year.
Kenyan Janeth Jepkosgei Busienei took bronze.
