London - Day two highlights for the IAAF World Championships on Saturday:
Men's 100m semi-finals, final
Usain Bolt will have to work on a proper start from blocks he called the worst he's ever used after struggling in Friday's heats. The Jamaican's power saw him through into the semi-finals, his American arch-rival Justin Gatlin, who has served a four-year doping ban, ignoring pantomime-like jeering to safely negotiate his heat.
Women's 100m heats
Jamaica's Elaine Thompson and Dafne Schippers of the Netherlands headline the event in the latest saga of their not so friendly rivalry. The Jamaican has the upper hand on her fellow 25-year-old having beaten her in both the 100 and 200m finals at the Olympics. However, Schippers has ditched her coach for a specialist sprint one and believes she is better-equipped to challenge Thompson. Others not to be discounted are American Tori Bowie, who took silver in Rio and Ivorian veteran Murielle Ahoure, who looks to have recaptured the form that saw her take silver in 2013 behind Thompson's compatriot Shelly-Ann Price, who is absent because she is expecting her first child.
Women's 10,000m final
This could turn out to be quite an open race with question marks surrounding both Ethiopian stars, world record holder and Olympic champion Almaz Ayana and legend Tirunesh Dibaba. Ayana has shown nothing like the form of last year, this term hampered by injury whilst Dibaba has focused on road running but a strong showing in the London Marathon showed she is in top class form. At 32 she cannot be discounted from winning her sixth world title. Outside of the Ethiopian duo the Kenyan trio includes Alice Aprot, whose searing early pace in the event in Rio set the tone for Ayana to go on to glory although she paid for her exertions and failed to medal.
Women's 1500m semi-finals
Dibaba's younger sister Genzebe won her heat on Friday but judging by the powerful finish in the same race of South Africa's two-time Olympic and world 800m champion Caster Semenya she faces a tough defence of the title she won in 2015. Ethiopia-born naturalised Dutchwoman Sifan Hassan impressed in coming from eighth with a lap remaining to win her heat suggesting she might improve on her bronze from 2015. Kenya's Olympic champion However, all of them will have Kenyan Faith Kipyegon on their minds as the 23-year-old Olympic champion looks to be in fine fettle after cruising home in her heat.
Nafi Thiam goes into the heptathlon as hot favourite as she seeks to add the world title to her Olympic crown. The Belgian, a geography student at Liege University, produced one of the shocks of the Rio Games when, despite competing with torn elbow ligaments, she trumped Britain's defending champion Jessica Ennis-Hill in the gruelling two-day, seven-discipline event. Ennis-Hill has since retired, leaving Thiam with a clear chance of a second global victory.