Joao Almeida won the abbreviated sixth stage of the Tour of Switzerland on Friday ahead of his UAE team-mate Adam Yates, who retained the overall lead in Blatten.
The stage was shortened to 42.5 kilometres. It was originally planned to run 151.1km from Locarno, but snowpack made Nufenen Pass impassable and also ruled out an alternate route over the Furka Pass.
The stage still finished with a brutal seven-kilometre climb to Blatten and Yates attacked with three kilometres to go.
The Briton had won Thursday's fifth stage with a ferocious attack on the final climb, but this time he was caught.
Almeida shook off the other pursuers, including former Tour de France winner Egan Bernal and defending champion Mattias Skjelmose, and caught Yates with one kilometre to go. The Portuguese rider pulled away at the finish to win in 55 minutes 13 seconds.
"I think we were both really strong," said Almeida at the line. "He attacked quite far from the finish and I was just on the wheel of Skjelmose so it was perfect for me. In the end, I could catch him without bringing the other riders back."
Yates was four seconds behind with Skjelmose, a Dane who rides for Lidl-Trek, at nine seconds, and Colombian Bernal of Ineos at 15 seconds.
In the overall standings, Yates leads Almeida by 27 seconds. Bernal is third at 1:28.
Both Yates and Almeida are likely to be support riders for UAE leader and Giro d'Italia winner Tadej Pogacar, when the Slovenian launched his attempt to regain the Tour de France title on June 29.
Saturday's penultimate stage is a tough 118.1km circuit starting and ending in Villars-sur-Ollon and including three big climbs.
"Of course I want to win all the time," Almeida said. "But I would also respect my teammates as well so I'm happy for him also."