Team Sunweb's Arndt kept his cool in difficult conditions to earn victory at the conclusion of the 166.9 kilometres route from Valls to Igualada.

Arndt prevailed in a group of 20 breakaway riders following the hilly journey, which took place on slippery roads in the province of Barcelona. 

Alexander Aranburu Deba of Spain was second, with Belgium's Tosh Van der Sande third.

Edet, who rides for Confidis, took the red jersey after coming home in 11th place.

The 31-year-old Frenchman has a lead of 2min 21sec over Belgian Dylan Teuns of Bahrain-Merida, who ended the eighth stage in sixth.

Astana's Miguel Ángel López, who led the general classification before today's stage, is third in the battle for the overall title.

"It’s huge – there are no other words," said Edet.

"It’s a crazy thing. 

"I’m going to defend it this jersey, I’m going to give it my all."

The race continues with stage nine tomorrow, a mountainous 94.4km route from Andorra la Vella to Cortals d’Encamp.

Monday (September 2) is the first rest day.