Alejandro Valverde won his fourth Liege-Bastogne-Liege as tributes were held in memory of Michele Scarponi, who died in a training crash on Saturday.
The Italian, 37, collided with a van close to his home in Filottrano.
A minute's silence was held before the race, with race director Christian Prudhomme then leading tributes to "a rider who was loved and respected, a ray of sunshine in the peloton".
Republic of Ireland's Dan Martin was second, with Michal Kwiatkowski third.
"That was for you Scarponi," said Spaniard Valverde after crossing the line at the end of the gruelling 258km race in Belgium, one of cycling's one-day Spring Classics.
"He was a very god friend of mine and when I heard the news, it was terrible. All of the prize money is going to his family. The race was unbelievable today, the team did a fantastic job."
More to follow.