Caster Semenya should definitely be taken seriously in the 400m.
Semenya, the scrutinized Olympic 800m champion, won a 400m race in a massive personal best in the final Diamond League meet of the season in Brussels on Friday.
The South African clocked 50.40 seconds, taking .34 off her personal best set earlier this year. It was her first time racing 400m against a top-level international field.
Semenya came from behind in the race and beat the Rio Olympic third- and fourth-place finishers.
Her time would have placed fifth in Rio, but well behind gold medalist Shaunae Miller of the Bahamas (49.