The 19 - year - old Munyai was second in 20.10 .
The 19 - year - old Munyai improved the mark of 20.16 by Riaan Dempers from 1995 .
The 19 - year - old Munyai was second in 20.10 and improved the mark of 20.16 by Riaan Dempers from 1995 .