The German jostled with Clément Champoussin of AG2R-Citroën, Cofidis rider Jose Herrada and Quinn Simmons of Trek–Segafredo at the conclusion of the 178-kilometre race from Locarno to Moosalp.

A bike throw by Denz proved to be decisive, as he won in a photo finish with a time of 5 hours 11mins 14secs.

Britain's Geraint Thomas of Ineos Grenadiers and Israel–Premier Tech's Jakob Fuglsang of Denmark did not challenge for the stage win, coming in eighth and tenth place respectively some 2mins 14secs off the pace.

However, the pair did enough to lead the tour after stage five winner Aleksandr Vlasov of Bora-Hansgrohe was forced to end his involvement following positive test result for COVID-19.

Fuglsang is now out in front on an overall time of 27 hours 30mins 30secs and Thomas is just a second behind.

"This is my greatest success so far as a professional," Denz said after his victory. 

"Fausto Masnada set a tremendous pace and I had trouble following. 

"But I had excellent information from the support vehicle and knew that the climb flattened out a bit at the top. 

"So I just stuck with it. 

"And I also knew that I wasn't a bad sprinter."

Another Bora-Hansgrohe rider, Sergio Higuita of Colombia, finished in between Thomas and Fuglsang in ninth on the same time, leaving him third in the overall standings with a 10 second deficit on Fuglsang.

Higuita also currently leads the race for the white jersey, given to the best young rider, by some 36 seconds.

Stage seven of the Tour de Suisse will take place tomorrow, with another mountainous 196km ride from Ambri to Malbun providing consecutive ascent finishes.