Pep Guardiola is currently going through the worst season of a coaching career that had previously been almost perfect.
However, even the best coaches make mistakes from time to time and Guardiola recently admitted one that made him regret it.
It was Guardiola's decision to allow a player to leave too soon that is still on his mind.
However, Guardiola did not discuss City's decision to sell Cole Palmer to Chelsea for £42.5m in September last year.
Palmer has since scored 34 goals and 17 assists in 52 Premier League games for his new team.
But the man Guardiola claims he should have kept longer was Jesús Navas.
Pep Guardiola admits having made a “mistake” in the transfer as Manchester City manager
That mistake was not selling Cole Palmer to rivals Chelsea for £42.5m in September 2023.
Guardiola says he regrets letting Spanish star Jesús Navas leave City on a free transfer in 2017
Navas left the Etihad Stadium in the summer of 2017 at the end of Guardiola's first season in Manchester.
The Spanish star had been with City since 2013 and racked up 183 appearances in all competitions.
Upon leaving City, Navas rejoined Sevilla on a free transfer and enjoyed another seven and a half seasons in southern Spain before opting to retire.
The 39-year-old's playing career officially ended on New Year's Eve, when his contract expired.
However, he will remain at Sevilla as a non-player after an offer from the club president.
Sevilla held a ceremony to celebrate Navas' career this week, prompting Guardiola to reach out.
Guardiola told his former player: 'Thank you for the gift of having spent a year together. You don't know how much I regret letting you go.
'I would have loved for you to stay here longer, but sometimes you make mistakes.
Navas played 183 games in all competitions for City and won three major trophies.
Guardiola and Navas photographed celebrating a victory over Manchester United in September 2016.
Sevilla legend Navas, 39, retired from the game when his contract expired on New Year's Eve
'Congratulations to all the Sevillistas for having had such an extraordinary player and a person who defines Sevillismo.
'For many years, Sevillistas, don't let him escape. Keep him close and with all of you. Farewell.'
Navas won a Premier League title and two EFL Cups during his four years at City.
He won eight trophies in his two spells with Sevilla, including the UEFA Cup/Europa League on four occasions.
The right-back also achieved international success with Spain, winning the World Cup in 2010 and the Euro Cups in 2012 and 2024, as well as the 2022-23 edition of the UEFA Nations League.