Defending champion and world-record holder Wayde van Niekerk of South Africa crashed out of the men's 400 metres at the Tokyo 2020 Olympics after finishing fifth in the semifinal on Monday.
Former Olympic champion Kirani James of Grenada posted the quickest time in the semifinals.
Van Niekerk suffered a number of injury setbacks since his world record-breaking run five years ago in Rio de Janeiro and his exit was not a surprise after he scraped through to the semifinals by finishing third in his heat.
World champion Steven Gardiner of the Bahamas overtook Van Niekerk and his other opponents with smooth strides in the last 50m to win the race and qualify third-fastest in 44.14.
"I expected way more from myself and it obviously didn't work out the way I wanted it to, but it is what it is. We move forward," Van Niekerk said.
James, who claimed the 400m gold at the 2012 London Games and a silver behind Van Niekerk in Rio, won the evening's first semifinal in a season-best time of 43.88 seconds.