Noah Lyles, who tested positive for COVID on Tuesday and took bronze in the Olympic 200 metres sprint on Thursday, said the virus "definitely" affected his performance, and that he had been coughing through the night ahead of the race.

The U.S. athlete, who has asthma, was taken off the track in a wheelchair after the finish as he battled to catch his breath and tore his singlet half off.

"I was quite light-headed after that race. Shortness of breath, chest pain, but after a while I could catch my breath and get my wits about me," Lyles said later.

"It definitely affected my performance. I've had to take a lot of breaks… I was coughing through the night. I'm more proud of myself than anything, coming out here to get a bronze with COVID."

Lyles had woken up in the middle of the night Tuesday with chills, aching, and a sore throat, he said, and his team then got him on "as much medication as we legally could to make sure my body could keep the momentum going."

In a later post on Instagram, Lyles, who took gold in the 100m sprint last week, said he believed his Olympics was over, indicating he will not compete in the 4x100m and 4x400m relays he was targeting.

Even with the virus, Lyles, a star of the Netflix series "Sprint", put on his usual show on coming out for the 200, jumping and revving up the roaring crowd.

"I already had a bunch of energy," he said. "This is by far the best day I've felt out of the last three days. Still not 100% but closer to 90 to 95%."

Letsile Tebogo won the 200 to claim Botswana's first ever Olympic gold, saying afterwards: "I can't be the face of athletics as I'm not a loud or arrogant person like Noah."