Caster Semenya targets sub-two minute final

South African 800m runner Caster Semenya has said that she needs to run under two minutes to 'contend' in Saturday's final.

The 21-year-old ran a personal best of 1:55.45 when she was 18 to win the 2009 World Championship final in Berlin but has not run as fast since.

Speaking after today's opening Olympic heat, Semenya said: "It was a tactical race. I wanted the race to be a fast one.

"I have to run a sub-two [minutes] race to be a contender."

Semenya finished second in the heat as America's Alysia Johnson Montano ran away from the field from start to finish in irregular 800m tactics.