The Swiss rider featured in a six-man breakaway on the 174 kilometre stage from Le Locle to Morges.

With the peloton starting to close in as they built towards a sprint finish, Kung made an initial attack from the breakaway with 30 kilometres to go.

The effort cut the group in half but Kung accelerated again with 20 kilometres to race to move solo, with a lead of nearly 1min 20sec over the peloton

He benefitted from increasingly wet conditions on the road which slowed the main field’s advance, with Kung able to preserve much of his lead.

The Groupama-FDJ rider crossed the line in 4 hours, 10 min and 59 sec.

It was Kung’s third stage win at the International Cycling Union (UCI) WorldTour race, having enjoyed success in 2015 and 2017.

Ireland’s Sam Bennett won the sprint for second, the Bora-Hansgrohe rider finishing 59 seconds adrift of the stage winner.

He was followed across the line by Italy’s Sonny Colbrelli.

Slovenia’s Primož Roglič finished in the main field to preserve his lead in the general classification.

The defending champion has a 10-second advantage over second-place Rui Costa of Portugal, a former world champion.

France's David Gaudu is a further two seconds back in third.

The race continues tomorrow with a 160km stage in Romont.