After a fierce battle to get into the early breakaway, a massive group rode clear. Totalling 26 riders, the likes of Michael Matthews, Mads Pedersen, Sepp Kuss, Bauke Mollema and Ilan van Wilder were all up the road. Best placed on GC however, was BORA - hansgrohe rider Patrick Konrad who started the day 8:43 down on the Maglia Rosa, Geraint Thomas.
They were soon joined by a further four attackers, taking the total in the lead group up to 30 different riders.
At the intermediate sprint, Pedersen and Matthews battled it out to try and recoup some of their losses in the points classification to the leader, Jonathan Milan with Pedersen taking the maximum 12 points on offer leaving Matthews to pick up 8.
With INEOS keeping the breakaway on a tight leash early on the time gap was still around 3 minutes with 100km left as the rain returned once again.
It was doubtful a 30-rider breakaway was ever going to coexist for long and with around 92km to cracks started to form with five riders attacking off the front.
As the rest of a frustrated breakaway argued instead of chased, the lead group that had dropped to four riders was soon ahead by over two minutes.
With 50km to the finish line, Nico Denz, Alessandro Tonelli, Sebastian Berwick and Toms Skujiņš had an advantage of 2:38 over the nearest of their breakaway challengers and nearly 9 minutes to the peloton.
The remainder of the breakaway behind the four leaders was splintered across the course with numerous groups of riders somewhere in between the quartet at the front of the race and the peloton, at various time gaps.
As the leaders reached the final climb of the day the attacks came. Skujins was the first to really up the pace and Tonelli could stay in contact no longer leaving just a trio at the front of the race
Denz looked likely to join Tonelli out the back but after a fierce battle he crested the top of the climb alongside Skujins and Berwick.
Despite a few nervous moments on the descent, the leading trio all stayed upright meaning they had the flat final 15km or so to battle it out for the stage win.
With 12km to go it was Denz who made the first move. Although Skujins was able to quickly come across, Berwick instantly struggle and it seemed as the stage win was now a head-to-head battle.
The Australian wasn't giving up without a fight though and the Israel - Premier Tech rider regained contact as the leaders reached 9km to go.
With plenty of time to play cat-and-mouse, the leading trio reached the final kilometre almost at a crawl with the riders looking at each other and none wanting to take to the front.
It was Denz who was at the front though and the German led from the front, powering ahead of his rivals and taking a deserved win ahead of Skujins in second and Berwick in third.