The Italian timed his sprint to perfection in Plouay, diving out from a tight gap in the pack and finding space along the left-hand side of the road. He edged out rivals Alexander Kristoff (Katusha-Alpecin) and Sonny Colbrelli (Bahrain Merida) at the line to claim his fourth win in little over a week.
Team Sky did a great job imposing themselves across the 239.7-kilometre event, arriving at the front in numbers to control the pace following the feedzone. Philip Deignan led the line, and shortly after Tao Geoghegan Hart bridged across to a promising attack, which quickly swallowed up the early breakaway.
That forced other teams to step up and chase, with Michal Kwiatkowski riding attentively behind and looking to follow any counter attacks. In the end it came back together, with Owain Doull pushing hard to catch a final group of escapees. Viviani dragged himself over the tough final rise, and after Michal Golas strung out the pack into the final kilometre, the Italian did the rest in style.