Adam Yates turned the rolling hills of Basque country into Britain's twin peaks by surging into the Tour de France leader's Yellow Jersey.
In an emotional and unique finale in Bilbao, Yates outlasted his identical twin brother, Simon, to win his first-ever stage on Le Tour by four seconds.
Although they are from the same family in Bury, the pair race for different teams and, when they hit the front with five miles to go, Yates admitted: “At first I didn't know if I should work with him.”
They are the first brothers to finish one-two on a stage in the world's most celebrated cycle race since Luxembourg's Andy and Frank Schleck in 2011.
Yates, 30, expects to spend the next three weeks as his UAE Emirates team-mate Tadej Pogacar's flank engine, and Slovenia's two-time champion looked in ominous form as he crossed the line third, just 18 seconds back, in a group containing defending champion Jonas Vingegaard.
But Yates is one of only 10 British riders ever to wear the fabled maillot jaune, and just the fifth – after Chris Boardman, David Millar, Mark Cavendish and Geraint Thomas – to do so on the first night.
He said: "We tried to set the climb up for Tadej and he attacked, but then it was a headwind on the descent (towards the finish). My brother came across to me and we started to work together.
"At first I didn't know if I should work with him, but I asked on the team radio and they said, 'Go for it'. I'm speechless.
“I knew he was going good because I speak to him every day. My brother and I are close and to share this experience with him is really nice.
"I wish he would pull a bit easier because he almost dropped me at one point, but I'm just super happy.
"I wore yellow a few years ago, the Covid year in 2020, which was also a special moment, but really I just want to keep my feet on the ground.
“We're here for Tadej - he's the boss, he's shown before he's the best in the world and over the next few weeks I'm sure he's going to show that again."
Simon Yates, riding for Team Jayco-AlUla, won the Vuelta a Espana five years ago, claimed cramps on the final climb hampered his efforts to beat his brother to the line.
He said: "There was a bit of cat and mouse over the top, and Adam rolled to the front.
"At first when he saw me coming across, I think he was put in a difficult situation. I knew it was going to be tricky yet at the same time I had to take the opportunity.
"Normally on a finish like that I wouldn't beat Pogacar or (Jonas) Vingegaard in a real fast sprint, so to get away with Adam was maybe a chance.
“We're pretty close normally but I had some cramps in the final. It was a humid day so unfortunately he got the better of me but I'm sure there are more chances coming."
British sprint royalty Cavendish, going for a record 35th stage win – he currently shares the honour with Belgian legend Eddy Merckx – was never going to be in the hunt on the 113-mile Grand Depart from Basque country which started and finished in Bilbao.
Five categorised climbs, finishing with a brutal 20 per cent gradient on the Cote de Pike, were too much for the speed merchants and they spilled out of the back of the peloton like autumn leaves.
The Manx missile's first likely chance to go past Merckx, and out on his own into the history books, will be Monday when the peloton arrives on French soil for a flat run into Bayonne.
Spain's Enric Mas became the first rider to abandon the race after a collision with Richard Carapaz on the descent of of Cote de Vivero with around 13 miles to go.
