Team GB runner Jessica Judd collapsed from exhaustion at the end of her 10,000 metres race which took place in brutal conditions.
Temperatures in the Tokyo Stadium reached well over 30 degrees celsius and were accompanied by 80 percent humidity as the long-distance athletes paid a heavy price for their efforts.
Judd finished the race in 17th place, but immediately dropped the the ground after she crossed the line. She was seen begging for water for several minutes before her British teammate Eilish McColgan eventually brought her a bottle.
The 26-year-old was looked at by medical staff on site after the race, and was escorted off the track in a wheelchair after she regained her bearings.
After she had recovered, Judd said to Eurosport: "That is the closest I've come to not finished. When it gets to you, it gets to you. I was desperate for water, I've never been this sweaty in my life."
McColgan, who finished ninth, was quick to emphasise the gruelling nature of the race, and remarked on just how talented the race leaders are. She said: "It's definitely one of the hardest races I've ever run in my life.
"I couldn't have done much more.
"Those girls at the front, it's absolutely incredible they can run those times in this weather."
Four of the race starters were unable to complete the race in light of the savage heat.
Sifan Hassan from the Netherlands won her second gold medal and third in total of the Tokyo 2020 games after already having triumphed in the 5000 metres and picking up bronze in the 1500 metres.
Hassan herself was clearly affected by severe dehydration as she crossed the finishing line, totally unable to celebrate her extraordinary achievement and appealing desperately to officials for some water.
The extreme temperatures in Japan have been a subject of some controversy during the two weeks of competition.
Almost 20 percent of the field in the 50km race walk failed to complete the course with many of those who did finish bouts of illness throughout the event.
Tennis star Daniil Medvedev was heard complaining about the schedule during his match against Fabio Fognini, asking: "If I die, who will take responsibility?"
Indeed, Paula Badosa was forced off the court after suffering sever heatstroke, leaving the arena in a wheelchair.
