The mood at the start was one of reflection, with a minute of applause in dedication to Michele Scarponi, who tragically lost his life while out training on Saturday.
With 258km on the agenda and eight riders up the road early on, Movistar began setting a tempo on behalf of pre-race favourite Valverde. Yet the gap spun out to over 13 minutes as the race made the turn at Bastogne, and after three hours Team Sky began to lend their weight to the chase via Pete Kennaugh.
The first big attacks began to fire on the Col du Maquisard, before Sebastian Henao came to the fore with an acceleration on the famous Cote de La Redoute.
The first big move from Sergio came on the Côte de la Roche-aux-Faucons, splitting the bunch behind, before another dig on the Cote-Nicolas.
Moscon working hard on the run-in, with Stephane Rossetto (Cofidis) final rider to be reeled in from a brave breakaway with 9km to go.