On the 175.4-kilometre route from Saint-Chamond to Saint-Vallier, it was in the final kilometre that the Welshman made a surprise attack to claim the victory.

The 2018 champion used a 180-degree turn to steal a lead on the peloton and managed to hold off stage three winner Italy's Sonny Colbrelli of Team Bahrain Victorious on the line.

He received a bonus of 10 seconds, while Colbrelli got six and Spain's Alex Aranburu Deba of Astana-Premier Tech four seconds for finishing second and third.

A total of 43 riders came in under the time of 4 hours 2min 15sec, including the lead cyclists.

Spain's Carlos Barbero of Team Qhubeka Assos and Denmark's Mads Würtz Schmidt of Israel Start-Up Nation were fourth and fifth.

With just three stages to go, Thomas remains in contention for the 2021 title and is now just 14 seconds off the lead of Pöstlberger.

Kazakhstan's Alexey Lutsenko of Astana-Premier Tech remains a second adrift of the Austrian, followed by Denmark's Kasper Asgreen of Deceuninck Quick-Step who is six seconds behind after picking up some bonus time today.

Spain's Ion Izagirre, also of Astana Premier-Tech is nine seconds behind in fourth, while Dutch rider Wilco Kelderman of Bora-Hansgrohe is 13 seconds adrift in fifth - a second ahead of Thomas and Belgium's Ilan van Wilder of Team DSM.

Tomorrow, riders will take on a 167.5km route from Loriol-sur-Drôme to Le Sappey-en-Chartreuse on the sixth stage.