Adam Yates was born a few minutes after his twin brother Simon, but on Sunday the UAE Emirates rider was first to the finish line just ahead of his sibling to grab his maiden Tour de France victory.
Adam's win came 10 years after Simon beat him in a one-two in the fifth stage of the Tour de l'Avenir in Morzine.
Adam attacked in the final descent to Bilbao on the Tour's opening stage and was soon joined by Simon, who is riding for the Jayco-AIUla team, as the duo opened a 20-second gap going into the final uphill drag.
Adam was the stronger in the end, finishing four seconds ahead of his brother, denying him a third stage win on the Tour.
"It's super special to me, a one-two in the Tour de France for brothers, not many people can say they've done it, it was nice we did it," Adam told a news conference.
"It's super nice to share this with him."
The previous brotherly double on the Tour was in 2011, when Luxemburg's Andy Schleck finished first in Serre Chevalier some two minutes ahead of second-placed Frank.
Simon, who won two stages in the 2019 Tour, sounded much less content than his brother, saying: "I'm happy for him, but I'm disappointed."
In the descent and on the flat part before the last uphill kilometre, Adam did not work in tandem with his brother, his main job being to help two-time Tour champion Tadej Pogacar.
"When we got away together I told him I couldn't work together but with four, five kilometres to go, Tadej gave me the word to go because there was some confusion behind," he explained.
Both their parents were on the road to see the peloton pass, but they were probably not expecting a family one-two.
"I saw them on the course, they were in a camper somewhere along the coast," said Adam, who added he and his brother, who both live in Andorra, are 'super close'.
"We've been seeing each other every day for the past 10-15, years," he said.
"During the preparation for the Tour he's been doing his own thing and I've been doing the Criterium du Dauphine. But when we're both back home, we live five minutes away and we see each other every day."
It may soon be time for payback with Simon surely out for revenge.
"I'm sure he'll be a pain in the ass along the road," said Adam, who will soon go back to his domestique duties for Pogacar.
"He is the best rider in the world. If I can cause some carnage (to help him win the Tour)...," he said with a smile. (Reporting by Julien Pretot; Editing by Toby Davis)