RIO DE JANEIRO — Bursting out of the blocks in lane eight, Wayde van Niekerk didn’t see another runner during the entire Olympic 400-meter final.

He didn’t need to. It was just him against the clock.

The 24-year-old South African sprinter broke Michael Johnson’s 17-year-old world record on Sunday night in Rio de Janeiro, leaving two of the greatest one-lap runners of this era in his dust. Van Niekerk finished in 43.03 seconds — 0.15 seconds faster than Johnson ran in 1999. To think, Johnson’s mark was considered one of the almost untouchable records in track.