Argentina's Enzo Fernández completed his move from Chelsea to Manchester City in the final hours of the summer transfer window, after the two clubs reached an agreement worth £125 million.
City confirmed the five-year signing in an official statement released in the early hours of Wednesday morning.
The deal landed less than two hours after City announced the £65 million signing of Everton winger Iliman Ndiaye.
Enzo matches Isak
Fernández's transfer equals the Premier League record, previously set by Liverpool with the signing of Alexander Isak, according to "The Sun".
Aged 25, the midfielder underwent a medical before putting pen to a long-term contract. He reunites with his former Chelsea coach, Italy's Enzo Maresca, who succeeded Pep Guardiola over the summer.
City had opened direct talks with Chelsea on Monday. The negotiations then accelerated in the closing hours of the window to get the deal over the line before the deadline.
Fernández had pushed to leave Chelsea since March, and Maresca saw him as a key midfield addition, especially after several players left that position during the summer.
Chelsea had expected their player to stay. They set a deadline of 14 August for offers of no less than £120 million, and City made no bid during that window before everything shifted as the market neared its close.
Enzo's first words after signing for City
Fernández told his new club's website after signing: "Manchester City is the most successful club in England in recent years. Every player wants to be part of a club like this, because everyone knows how good the management is at Manchester City."
He added: "I couldn't be happier to be here, and I'm ready for the challenge of helping the team continue to win titles. It's a club built for success. If you look at the make-up of the squad, you'll find quality in every position. I want to learn from my new team-mates and become a better player."
He continued: "I always make sure to keep developing my level. Everyone who has worked with me knows how hard I work in training every day, and how much I give during matches. I give everything I have, and I can promise Manchester City that I will continue to do so now that I've joined the club."
The Argentine went on: "I would like to thank Hugo, Enzo, Khaldoon, and everyone at Manchester City who made completing this deal possible. I want to repay the trust they've placed in me, and to prove it as soon as possible."
An emotional farewell
Fernández also said goodbye to Chelsea's fans with a message on his social media accounts, revealing just how hard the days leading up to his Stamford Bridge exit had been.
He wrote: "I want you to know that these days have not been easy for me, and writing these words is not easy either. The truth is I have not been in a good state."
He added: "Three years ago, Cobham and Stamford Bridge became a home for me and my family. I became attached to the people, the shirt, and the badge of this wonderful club."
He continued: "Thank you for all the love and support you have given me and my family throughout these years. I will never forget it. This group will give you many more reasons to be happy, and I will be happy for you too, never doubt that."
He concluded: "You will always remain in my heart, Blues fans. I will always wish you all the best. Always blue. Thank you, Chelsea."
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Chelsea coach Xabi Alonso, for his part, stayed largely tight-lipped about Fernández's future when asked about a possible departure after leaving the player out of the squad for one match.
The Spaniard said: "We'll see. We want the best for the team, and that's why we made our decisions, and whatever might happen before Tuesday evening we have to be aware of."
He added: "We're not sure, and we're preparing for all scenarios, but I'm confident that, whatever happens, we'll have a team good enough to compete in all the Premier League matches from Wednesday onwards."
Fernández had earlier hit out at Chelsea's management after Maresca's dismissal last January, unhappy at the coach's departure mid-season.
He said in earlier comments: "I don't understand it. Sometimes there are things that we players don't understand, and how and in what way they try to manage things."
He added: "It's clear that his departure hurt us a lot, especially in the middle of the season, because that cuts everything off. We had an identity, and he gave us a clear system, even if football has good times and bad times."
Fernández joined Chelsea in January 2023 from Benfica for £106 million, a British record at the time, and went on to win the UEFA Conference League and the FIFA Club World Cup with the club.
The player and his agent, former Argentina international Javier Pastore, made his desire to leave public over the summer. His name was also linked with Real Madrid before the Spanish club issued a statement confirming they were not pursuing the deal.