Day 4 Preview: Usain Bolt will not defend his 200 metres crown, one he has held since setting a world record 19.19 seconds in Berlin in 2009. It could well come down to a battle between South Africa’s world and Olympic 400 metres champion Wayde van Niekerk and Botswanan rival Isaac Makwala, both seeking a first 200/400 metres world double since Michael Johnson in Gothenburg in 1995. Aries Merritt could provide the fairytale that the athletics championships need after Justin Gatlin denied Usain Bolt his golden farewell in the 100 metres. The 31-year-old American is one outstanding performance away from repeating his Olympic winning feat on the same track in 2012 and just two years after a kidney transplant. His biggest threat will be Jamaica’s Olympic champion Omar McLeod who looked to be in ominously good shape and is determined to break Merritt’s world record in the final. The Women’s 1,500 metres finals will see Caster Semenya, South Africa’s defending double Olympic 800 metres champion and two-time world gold medallist aiming for an audacious middle-distance double. Although her career has been mired by arguments over her elevated levels of naturally occurring testosterone, Semenya is happy to focus on her performances on the track. Challenging Semenya will be Ethiopia’s Genzebe Dibaba and Netherlands’ Sifan Hassan. With inputs from AFP.