American artistic swimmer Anita Alvarez was rescued from the bottom of the pool by her coach after fainting at the World Aquatics Championships.
The 25-year-old was not breathing and had sunk after completing her routine in the solo free final in Budapest.
Her coach, Andrea Fuentes, pulled Alvarez to the surface before she was taken away on a stretcher.
The US swim team later released a statement from Fuentes saying Alvarez "feels good now".
Alvarez previously fainted following a routine during an Olympic qualifier in Barcelona last year, with Fuentes also rescuing her on that occasion.
Of the more recent incident, Fuentes said: "Anita is OK - the doctors checked all vitals and everything is normal - [her] heart rate, oxygen, sugar levels, blood pressure etc.
Spanish newspaper Marca reported four-time Olympic medallist Fuentes as saying she had jumped in "because the lifeguards weren't doing it".
And speaking to Spanish radio, she said: "It felt like a whole hour.