Women's 800m: Will Nyairera survive Semenya's onslaught?

Nyairera and Caster Semenya

Olympic 800m bronze medallist Margaret Nyairera has a huge task ahead as she battles for top spot at the IAAF World Athletics Championships in London tonight.

Nyairera will renew her rivalry with Olympic champion Caster Semenya of South Africa and Burundi's Francine Niyonsaba, the Olympic silver medallist in Rio Olympics. She will team up with Eunice Sum and Emily Cherotich.

Kenya has won two gold medals (Janeth Jepkosgei in 2007) and (Eunice Sum in 2013) in the World Championships' history.

Sum, third in Beijing and winner in Moscow in 2013, also toes the line, while USA's Brenda Martinez also produced a season's best in Monaco and heads to London in confident mood.

Cherotich, silver medallist in Africa Championships in Durban, graduated from 400m after missing out on team spots to Moscow Worlds and Glasgow Commonwealth Games and will be out to carve a niche for herself.

The battle comes against Semenya's sublime form and the last time she was beaten over 800m was almost two years ago as she was eliminated at the semifinal stage of the IAAF World Championships in Beijing. In the intervening period, the 26-year-old produced 15 sub-two-minute runs, including four under 1:56.

The South African, who will be aiming for her third world title following victories in 2009 and 2011, remains the favourite. [Jonathan Komen and IAAF]