Inaki Williams always knew his brother Nico was special, even if his younger sibling used to get so nervous he would ask Inaki, already a star in Bilbao, not to watch his youth games at the Athletic Club academy.
He helped raise Nico while their parents worked tirelessly to make ends meet, but also paved the way for his brother and other sons of immigrants to represent a club whose policy of only fielding players born or raised in the Basque Country inevitably meant the squad has historically reflected the predominantly white society around it.
Inaki, 29, was not the first player of African heritage to represent the club - that was Jonas Ramalho, son of an Angolan father and Basque mother, in 2011 - but he is the first black player to establish himself at San Mames, having made more than 300 La Liga appearances, including an unprecedented 251 in a row.
Nico, eight years his junior, is, in Inaki's words, now "making waves in football" too, and any nerves the youngster feels these days are channelled into realising childhood dreams of performing on the biggest stage alongside his big brother, mentor and guardian.
"As an older brother, it makes me really proud to see how he has grown, to see how he is improving as a footballer. He has no ceiling," Inaki tells BBC Sport. "I'm here to help him, to teach him and give him everything he needs."
It is a journey that began long ago, and a long way from Bilbao. Their mother, Maria, was pregnant with Inaki when she left Ghana with father Felix in search of a better life.
The couple crossed part of the Sahara barefoot. Inaki only learned the full extent of their story when he was 20. He had known his father had problems with the soles of his feet, but not that scorching sand was the reason why.
Felix and Maria made it to the Spanish territory of Melilla in north Africa, jumping a border fence, but were detained by the civil guard.
A lawyer advised them to lie, to say they were from war-torn Liberia instead and seek political asylum.
He arranged help in Bilbao from Catholic priest Inaki Mardones, who met the couple at Abando railway station when Maria was seven months pregnant, found them an apartment and took them to hospital for Inaki's birth. Mardones baptised the future star, even gave him his first football shirt, and became his godfather.
He is whom Inaki takes his name from. Not that settling in Spain made life easy for the family. They were given state housing in Pamplona and worked any jobs they could. Felix moved to London in search of more opportunities, working the turnstiles at Chelsea's Stamford Bridge, and Inaki - still a child - stepped in to help his mum raise Nico.
"We had to suffer a lot," says Inaki, who would contribute to the family finances by refereeing football matches before his gift for the sport was enough to bring Felix home and end his search for work.
"Thanks to God we are all here together now, living a really good life. My parents are getting to watch their sons prosper, which is why they came here. Everything we do is for our parents."
On Athletic's radar for several years before officially joining the youth set-up aged 18, Inaki made his senior debut two years later in December 2014, sporting the same red and white jersey he wore as a boy.
"Inaki had a very difficult life when he was very young," explains Athletic sporting director Mikel Gonzalez. "He knows what his responsibility is, so you can see him like a superhero. His mum is, for sure."
Maria would always be there to watch her boys' matches. Nico joined the academy aged 12, when Inaki was already breaking into the first team, and began to forge his own path to stardom.
"It was incredible watching him play," says former Athletic head coach Gaizka Garitano. "So easy. He was very fast, incredible speed. Even more skilful than his older brother.
"Their mother was key for their improvement. Not only in football but also in the way they are, the respect of everybody. It was very tough for them, Inaki especially.
"Inaki lived this situation at home very hard, without any money.
"The character of Inaki is based on that time. He is very humble, always trying to learn from the coaches, and is very respectful."
On Saturday the brothers will try to help Athletic win a first major trophy in 40 years when they face Mallorca in the Copa del Rey final in Seville.