Wayde van Niekerk ran the fastest 400m of the season in Lausanne on Thursday night.
It was the first real 400m race this year for the reigning Olympic and World Champion.
The 24-year-old ran a controlled 43.62, the joint 11th fastest time ever over the distance, easing up having passed challenger Isaac Makwala in the final straight.
The time was also a meeting record, breaking the mark set by Michael Johnson 21 years ago.
It's the second record held by Johnson that the South African has broken in the past eight days. Last week in Ostrava, van Niekerk broke Johnson's 17-year-old 300m world best.
Olympic champion Wayde van Niekerk eases down over the line on his way to set a WL, DLR and MR of 43.62! #LausanneDL pic.twitter.com/xfaVTPMybj
— IAAF (@iaaforg) July 6, 2017
This year van Niekerk has run 9.94 for 100m, 19.84 for 200m, 30.81 for 300m and 43.62 for 400m.
The big question going into next month's World Championships is not whether he will take the 400m title but rather, can he break his own world record and go sub-43?