Phelps hails "unbelievable" Hafnaoui

Hafnaoui was the slowest qualifier but, from lane eight, held off fancied Australian Jack McLoughlin and American Kieran Smith for a huge upset.

Michael Phelps hailed Ahmed Hafnaoui for his “unbelievable swim” on Sunday, saying the 18-year-old Tunisian’s shock victory in the men’s 400m freestyle was a great example of how swimming at the Tokyo Games is likely to have a series of wide open races.