Chinese star sprinter Su Bingtian, who set an Asian record of 9.83 seconds at last year's Tokyo Olympic Games, said on Thursday that he is unlike to repeat the magic performance due to a knee injury.

"I have not maintained good form this season. I just hope I can finish my race," said the 32-year-old after taking a test run at the Hayward Field Stadium, which will stage the postponed World Championships from July 15-24.

The venue is a lucky place for Su. It was from the first lane of the stadium that he ran under 10 seconds for the first time at the IAAF Diamond League in 2015.

He went on to rewrite history in the following years and finally became the first Asian man last year to enter the Olympics men's 100 meters final in 89 years.

He competed here for three more years in a row before being interrupted by an injury and then COVID-19. He took Eugene as a starting point and has many reasons to show gratitude.

"I went back to many places where I had taken pictures," he said. "I specially chose the first lane to try to find my old self."

He is scheduled to run the first round of men's 100 meters on Friday evening amid injury worries.

"This is my first race this season. After coming to the United States in late June, I have not felt well and suffered a minor injury to my knee during a training session in Jacksonville, Florida."

"My top priority had been the Asian Games in Hangzhou, but after the Asiad was postponed, I had to reschedule my training plan. That is tough."