Warholm dazzles in 400m hurdles as Biles makes dramatic Olympic return

Karsten Warholm smashed his own world record as he streaked to victory in the Olympic 400m hurdles on Tuesday while Simone Biles prepared for a dramatic return to action after a Games dogged by mental health struggles.

Norway's Warholm lit up the Olympic Stadium in the final event of the morning session, clocking a remarkable 45.94 seconds to destroy his previous world best by nearly 0.8sec.