So, typically, a move for Athletic's Kepa Arrizabalaga to the Santiago Bernabeu would have been the most natural thing in the football circle of life.
But, despite the 23-year-old – third-choice goalkeeper behind David de Gea and Pepe Reina in Spain's 2018 World Cup squad – emerging as one of the top talents in La Liga, it is at Chelsea where he will be expected to truly flourish.
The Blues' former first-choice goalkeeper, Thibaut Courtois, has gone to Madrid, leading directly to Kepa's arrival. It's a curious twist of fate that his departure from Stamford Bridge would pave the way for Kepa, who was so close to joining the European champions in January, to go the opposite way and replace the Belgian at Chelsea.
If Chelsea's 2-0 loss to Manchester City in the Community Shield was anything to go by, the idea of reserve goalkeeper Willy Caballero playing week-in, week-out wouldn't be much comfort to supporters – and the arrival of Robert Green doesn't do much to reassure, either.
100% - Kepa Arrizabalaga has saved the 10 shots on target he has faced against Real Madrid in La Liga this season. Lion. pic.twitter.com/T42lGGoLgj— OptaJose (@OptaJose) April 18, 2018
In making a move for Kepa the Blues eclipsed the previous world-record fee for a goalkeeper that was set by Liverpool in their acquisition of Roma's Alisson earlier this summer.
Kepa may be a relatively unknown name for Chelsea fans and Premier League watchers, but there's a reason that Real Madrid were so eager to move for him just a few months ago.
The keeper has already amassed 54 senior appearances for Athletic after coming up through their youth system, as well as earning one senior cap for Spain and representied his country at every youth level. He's amassed a reputation for his sharp reflexes, ability to move quickly on his feet and rapid movement.
He was the undisputed standout player in Spain's Under-19 team that won the European Championship in 2012, saving two penalties in a 3-3 semi-final shootout against France, and made his senior debut for La Roja in a 5-0 win over Costa Rica as Navas' replacement in late 2017.
11- Kepa kept more cleansheets than Iago Herrein (10), Keylor Navas (9) & Kiko Casilla (7) in La Liga since his debut in the top-flight. Renewal pic.twitter.com/FQ39I84vIF— OptaJose (@OptaJose) January 22, 2018
Having infamously lost out in their pursuit of Manchester United star De Gea due to faulty paperwork, the Blancos turned their attention to the young goalkeeper as an option to succeed 31-year-old Navas – whose contract expires in June 2020.
In January, Madrid were set to meet his then-release clause of €20m as it looked increasingly unlikely that Navas would be renewing his contract with Madrid.
But in an unexpected turn of events, Kepa decided to snub Madrid and stay at Athletic. He signed a fresh deal that would keep him at the club until 2025, with his release clause raised to €80m – describing Bilbao as his "home" and the club he believed he would develop the best at.
"I am very happy to continue in what I consider my home," Kepa stated at the time. "I have been here for almost 15 years, I joined when I was nine.
"It is a very important moment. for me and for my career, I am happy that after a long negotiation everything has come to fruition. Since I was little I've been an Athletic fan and always will be.
"Those who are close to me or more know me know that I am a person who likes to analyse everything before making a decision. I have taken my time and I want to thank the club that respected it to make my decision."
The Blues faced a race against time as to sign the young international before the Premier League transfer window closes on Thursday at 18:00 CEST – tasked with convincing the shot-stopper to move to England, despite Kepa having just renewed his contract.
Athletic, all along, were only expected to sell should Kepa's buy-out clause be matched.
The West London side were able to lure the goalkeeper with an improved after-tax salary and a seven-year contract, with Maurizio Sarri ready to hand him a key role in his new-look side.
Sarri on Thibaut Courtois' agent's comments: 'I am not interested in the agent. I want to hear if Courtois will say to me the same. I want players with a very high level of motivation.'#CommunityShield— Chelsea FC (@ChelseaFC) August 5, 2018
Chelsea were unwilling to part ways with Courtois unless they had an immediate, suitable replacement lined up, but made the move to let their Belgian leave and get the Kepa deal over the line before the start of deadline day.
The 26-year-old appeared unwilling to wait a further 12 months to grant his move with Sarri publicly telling Courtois to confront him personally if he wishes to leave the club.
And thus, Kepa's move to Chelsea was triggered by Courtois leaving for Real Madrid, the very club that very nearly prised the Spain international from Athletic in the first place.
Courtois' intentions were concrete – Real Madrid are the only he side he wishes to play for, and to prepare for life without him Chelsea have deemed Kepa to be the only suitable replacement.