Monday was a tough day for 2016 bronze Olympic medallist Henri Schoeman after he failed to finish the men's triathlon.
Schoeman was one of South Africa's medal prospects this year after producing a superb bronze performance at the 2016 Rio Olympics.
The 29-year-old was the lone triathlete in the men's race after Richard Murray withdrew on Thursday, stating his "health and heart wasn't ready".
Schoeman made history in 2016 by becoming the first South African to win a triathlon medal at the Olympic Games.
A lot of expectation was riding on Schoeman in Tokyo to reach the podium again. However, on Monday, the South African disappointedly failed to make the finish line.
National triathlon coach Lindsey Perry says that Schoeman has been plagued with a worrisome ankle injury that culminated in his demise in the triathlon.
"The heat wasn't the problem, we've been dealing with a running injury over the past few weeks and he literally did everything he could," said Perry.
"He was as positive as he could be, he had a great swim and had a good position coming out of the water.
"He rode really well, good positioning all the way until the final and conserved his energy well, but today wasn't his day."
Schoeman was in fourth position following his 1.5km swim and he eventually took the lead in the bike at 15km before ending 17th after the 40 km bike section.
However, as Schoeman descended on his final 3.5km, he pulled out with his ankle giving him more problems and ended in him not finishing the race.
"I could see from the first lap, he was in good shape, relaxed, but that 10km was enough to push through on the ankle so he'll be very disappointed," said Perry.
"We knew it was a long shot because it's been sore all week but he is a champion. He is in great shape, the best he has ever been in his life, but you've got to roll the dice."
Perry says that they are unsure what is causing the problem and are worried that Schoeman might not compete in the team relay this Saturday.
Schoeman's participation is key as he joins Murray, Gillian Sanders and Simone Ackermann in the team relay and if he is not ready, it'll end Team SA's triathlon run in Tokyo.
"We not exactly sure what the problem is, there is inflammation in the ankle, but we don't know what's causing it. We'll get him to a specialist and he'll be ready to compete properly again soon," said Perry.
"We're going to try (to get him in the relay), we're going to treat him and we hope so because if he doesn't, there's no relay. It's all a process."
Meanwhile, the women's triathlon sees Sanders and Ackermann kicks off at 23:30 SA time on Monday evening.
"Gill has had quite a tough two years, it was difficult for her to compete internationally because of Covid," said Perry.
"She qualified and her swimming has been better than its ever been in a few years and that's where she's been struggling. I think she's going to give everything, especially since what's happening in the relay.
"Simone is in good shape, every time she's raced this year, she has looked a bit better. She's a strong swimmer and her weakness is maybe the cycling," continued Perry.
"Her running has improved a lot. We probably shouldn't expect medals there, but I think we can hopefully get into the Top 10 then it'll be an outstanding day."
*Lynn Butler is in Tokyo covering the Olympics for Sport24.