The 193-kilometre route began in Sierre in Switzerland and featured a top-category climb up the Simplon Pass near the start before a mostly flat ride to Cassano Magnago in Italy, and was played out in heavy rain.

The peloton was content to allow an early breakaway race clear at the front, and the general classification group including Ineos Grenadiers rider Thomas and his closest challenger Primož Roglič of Slovenia and Team Jumbo-Visma finished 21min 11sec adrift of race winner Denz.

Bora-Hansgrohe’s Denz claimed his first Grand Tour stage win on Thursday (May 20), and repeated the feat as part of a chasing group which caught the race leaders.

Denz held off Israel-Premier Tech's Canadian rider Derek Gee and EF Education-EasyPost's Italian Alberto Bettiol in a final sprint to triumph in 4 hours 37min 30sec.

"I felt super good today and so I managed to get again into the breakaway," Denz said.

"We were lucky to close the gap just inside the final kilometre.

"I felt very good and when Bettiol launched his sprint I followed him and then I went full gas until the line.

"It was a very tough day but it ended well for me."

Groupama-FDJ rider Armirail is not expected to be a contender for overall victory, but can enjoy a day in pink after trailing Denz by 53sec in 15th.

Armirail admitted "the plan this morning was more about the stage win", and added: "Only once Geraint Thomas crossed the line, it became a reality in my mind but it’s hard to realise."

He had began the day 23rd in the general classification standings, but built a 1min 41sec lead over Thomas.

Roglič remains two seconds further back, and UAE Team Emirates' Portuguese rider João Almeida 22 seconds behind Thomas.

Almeida remains the leading young rider, with Team Bahrain Victorious' Jonathan Milan of Italy maintaining his points classification lead and his compatriot Davide Bais reclaiming the blue jersey for the mountains classification for Eolo-Kometa.

Tomorrow's 195km mountain stage from Seregno to Bergamo is set to feature several steep climbs.