Fuglsang, who is part of the Astana team, began the day 1min 15sec behind the BMC Racing rider in third place, with Britain’s defending champion Chris Froome lying second.

Porte found his lead being tested on the 175km stage from Albertville to Plateau de Solaison, which featured four tough climbs.

Accelerations from the Australian’s main rivals saw Porte lose several of his team-mates at the Col des Saisies.

The third climb of the day, the Col de la Colombière, proved key as Italy’s Fabio Aru and Spain’s Alejandro Valverde launched an initial attack.

Ireland’s Dan Martin, Fuglsang and France’s Romain Bardet set off in pursuit, with Team Sky's Froome eventually moving away from Porte near the summit.

Porte eventually fell over one minute behind the leading group, with Fuglsang launching an attack on the final climb in an effort to claim the overall victory.

He would take the stage victory in a time of three hours, 26min and 20sec, with Martin finishing 12sec back as the runner-up.

Crucially by winning the stage, Fuglsang secured a 10sec time bonus, which proved pivotal when Porte eventually crossed the line 1:15 down.

Fuglsang, who was the men's road race silver medallist at the Rio 2016 Olympic Games, would secure the overall title by the length of the bonus from Porte to become the first Danish rider to win the race.

Martin would finish on the podium for the second successive year by ending 1:32 behind the general classification winner.

Having faded in the closing kilometres of the stage, Froome missed the top three by 1sec at the International Cycling Union WorldTour race.