After losing consciousness in the water during the World Championships in Budapest on Wednesday, American artistic swimmer Anita Alvarez was in danger of dying before being saved by her coach Andrea Fuentes.

Omnanorama news reported that after seeing Alvarez go to the bottom at the conclusion of her solo free final routine, Spanish synchronised swimmer Fuentes, a four-time medalist at the Olympics, dove into the water.

Before being taken away on a stretcher, she received medical assistance next to the pool.

It was the second time Fuentes had to save Alvarez after the American and her swimming partner Lindi Schroeder jumped into the pool during an Olympic qualification event last year.

"Anita is much better, she is already at her best. It was a good scare, to be honest," Fuentes told Spanish newspaper Marca on Wednesday.

"I jumped into the water again because I saw that no one, no lifeguard, was jumping in. I got a little scared because she wasn't breathing, but now she's fine. She has to rest."