Adam got the better of identical twin Simon to triumph for the first time on a grand tour, while his UAE Emirates team leader Tadej Pogacar (24) finished third, also raising his arms in celebration.

Yates, who had set a devilish pace for Pogacar in the brutal climb shortly before the finish, pushed on in the descent to Bilbao, joined by his brother who is riding for the Jayco-AIUla team.

Adam was the stronger in the final uphill drag to prevail by four seconds, with Pogacar, who showed great legs in his first stage race since breaking a wrist in April, crossing the line 12 seconds off the pace.

"My brother came across to me and we started working together. At first, I didn't know if I should work with him, so I asked my team on the radio and they said 'Yeah, go for it'," said Yates after his maiden victory on a grand tour.

"We're really close. To share this experience with him is really nice - but I wish he would pull a little bit easier because he almost dropped me one moment! I'm super happy, I just want to keep my feet on the ground."

Overall, Yates leads his brother by eight seconds after picking up 10 seconds for the stage win, while Pogacar is 18 seconds off the pace.

Pogacar took a four-second bonus for his third place to take a slight advantage over defending champion Jonas Vingegaard (26), who was the only main contender to follow the Slovenian when he attacked on the Cote de Pike, 10 kilometres from the finish.

"It's a team win, it's like I had won myself. That Adam seized the opportunity to get the yellow jersey is a team dream coming true," said Pogacar.

Pogacar had benefited from Yates's hard work to open a gap 500 metres from the top with only Vingegaard and France's Victor Lafay (27) able to follow.

But the 2020 and 2021 Tour champion then slowed down, allowing a dozen riders to join them early in the descent, and eventually setting the stage for the Yates' brotherly battle.