Mader, 26, fell during a high-speed descent on the fifth stage between Fiesch and La Punt on Thursday, after an exhausting day marked by three ascents over 2,000 metres altitude.

He had been found "lifeless in the water" of a ravine below the road, "immediately resuscitated then transported to the hospital in Chur by air", organisers said.

But the next day, "Gino lost his battle to recover from the serious injuries he sustained," Bahrain-Victorious said in a statement.

"Despite the best efforts of the phenomenal staff at Chur hospital, Gino couldn't make it through this, his final and biggest challenge, and at 11:30am we said goodbye to one of the shining lights of our team," the team added.

"Our entire team is devastated by this tragic accident, and our thoughts and prayers are with Gino's family and loved ones during this incredibly difficult time."

Mader had enjoyed a strong start to the season, finishing fifth in the Paris-Nice race.

American rider Magnus Sheffield also fell on the same descent from Albula, during the most difficult stage of the race with multiple climbs. The Ineos-Grenadiers rider was hospitalised with "bruises and concussion," organisers said.

On Thursday, world champion Remco Evenepoel criticised the decision to compete on such a dangerous road.

"While a summit finish would have been perfectly possible, it wasn't a good decision to let us finish down this dangerous descent," the Belgian wrote on Twitter.

"As riders, we should also think about the risks we take going down a mountain."