Two-time Tour de France champion Tadej Pogacar was taken to hospital after crashing out of the Liege-Bastogne-Liege one-day classic.
The Slovenian, 24, crashed with Dane Mikkel Honore – who also had to pull out of the race – after 85km.
“He has a wrist injury and has gone to hospital for tests,” Pogacar’s UAE Team Emirates said.
The Netherlands’ Demi Vollering had earlier claimed victory in the women’s race.
Liege-Bastogne-Liege was Pogacar’s final race before heading for altitude training for the Tour de France, which begins on 1 July.
After winning this season’s Amstel Gold Race and the Fleche Wallonne, he had been aiming to become only the third man to complete a hat-trick of Ardennes classic wins.
Davide Rebellin in 2004 and Philippe Gilbert in 2011 are the only other men to complete the trio of wins.
Vollering makes history
Vollering’s victory, meanwhile, made her only the second woman to complete the hat-trick of Ardennes classic wins.
The 26-year-old’s second Liege-Bastogne-Liege win added to her recent success at the Amstel Gold Race and the Fleche Wallonne.
Compatriot Anna van der Breggen completed the Ardennes triple in the same season in 2017.
“It is unbelievable,” Vollering said.
“I felt the pressure as it is not every day you have the chance to do the treble.
“I really wanted to bring home this victory.”
Vollering broke clear from the peloton alongside Italy’s Elisa Longo Borgini with 10km remaining, but the Dutchwoman proved the stronger of the two in the sprint finish.