Wayde van Niekerk delivered a superb performance on Sunday night, storming to victory in a 200m street race in Boston.
The 400m world record holder, who was preparing to double over both distances at the World Championships in London later this season, charged across the line in 19.84 seconds.
Though it was the fastest time ever run by a South African athlete, the performance could not be recognised for record purposes as it was held on a temporary track without a bend.
He was well clear of American sprinter BeeJay Lee who took second place in 20.17.
National 100m record holder Akani Simbine took second place over his specialist distance in 10.21, narrowly edged out by Keston Bledman of Trinidad and Tobago who was credited with the same time.
Simbine and Bledman were separated by 0.001 at the finish line.
On Friday’s opening day of the Boost Games meeting, distance runner Dominique Scott had clocked 4:12.48 in the women’s 1 500m race.