Dutch rider Laurine van Riessen's bid for a women's Olympic keirin medal came to an end in a high-speed crash involving Britain's Katy Marchant at the Izu Velodrome on Thursday.
In their quarter-final heat, Van Riessen lost control of her front wheel and slid across into the path of Marchant, before both riders fell.
Van Riessen received medical treatment for several minutes on the track before she was put on a stretcher and carried away for further assessment.
The Netherlands team are yet to release an official update on Van Riessen's condition but the Dutch media reported that the 33-year-old, who appeared to have briefly blacked out, had regained consciousness before being transferred to hospital.
Van Riessen's Dutch team mate Shanne Braspennincx, meanwhile, delivered a brilliant ride in the final to claim the gold medal.
Braspennincx said she tried sending a message to Van Riessen but had to quickly switch her focus to the medal shootout.
"Coach Hugo Haak said that our team doctor is with her," Braspennincx told reporters. "He told me she's in good hands.
"I was worried about her, she went to the hospital, but at that moment I have to make the switch and focus on myself.
"I know it's part of (bike racing) but this is what you really don't want."
Marchant managed to get back up and finish the race but failed to qualify for the semi-finals.
"It's not my day is it," Marchant told reporters. "We were all fighting a bit on the inside and I'm not sure if someone hit into Laurine or what but she came down in front of me and I had nowhere to go."
Marchant said she would be back for Friday's individual sprint event, adding: "(I'm) a bit battered and bruised but I'm all right."
(Reporting by Hardik Vyas in Bengaluru; editing by Clare Fallon and Hugh Lawson)
