Kristoff (Katusha) outsprinted John Degenkolb (Giant-Alpecin) by a whisker at the finish in Rognan.
Six riders escaped for the day holding a seven minute lead for most of the way. The peloton slowly drew them back in, the final rider caught within the final five kilometres of the 176km stage.
"We didn’t want to use the team to pull for the entire day, so we used a few guys to help control. When I saw other teams come forward the gap came down fast and with 30 km to go I felt confident we had it under control and would bring them back," Kristoff said.
"I think I was a bit lucky because at the end I lost my teammates. I came on the wheel of Degenkolb and he timed the sprint perfectly, but lucky for me he had some technical issues with his gears jumping and I managed to pass him.
"I think actually I would have had trouble passing him if he had a smooth sprint."
Degenkolb agreed with Kristoff's sentiments.
“I felt really good and strong throughout the whole stage. The team did a great job in supporting me all day. In the finale, I was set up perfectly for the sprint and I think I could have won without the mechanical problems," Degenkolb said.
While the German has not yet taken a win since returning to the peloton in May after his horror early season crash, fighting closely for a victory is a considerable improvement given the extent of his injuries.
But the day was marred by a crash after the riders crossed the finish line.