Erik ten Hag wished Manchester United supporters "nothing but success, trophies and glory" after his dream of leading the club to further silverware this week came to an end.
The Dutchman led the Red Devils to victory in the Carabao Cup final and a third-placed Premier League finish during his first season, with a famous FA Cup triumph following against Manchester City last term.
But United limped home eighth in the league and a poor start to this campaign saw Ten Hag sacked just 116 days after minority owners Ineos, having considered his future, triggered a one-year extension.
Sporting Lisbon head coach Ruben Amorim was confirmed as his permanent successor on Friday, with the former Ajax boss releasing a farewell letter to supporters later in the day.
"Dear fans, let me start by thanking you," Ten Hag said in the statement released by his representatives SEG.
"Thank you for always being there for the club. Whether it was at a game far away or a tough match at Old Trafford, your support has been unshakeable. The atmosphere at Old Trafford has always been electrifying, thanks to you.
"I felt it many times. Also in away games, it gave the team and me an incredible feeling to hear the United chants taking over the opponents' stadiums, whether the game was in England, Europe or during the summer tours.
"I always enjoyed meeting Manchester United fans throughout the world. Walking the streets and being able to chat with fans in England, Europe, Asia, Australia, the USA - you inspired me and radiated a strong sense of unity.
"That's what makes United supporters so special. I want to thank you for giving me this feeling and for your support.
"I also want to thank the staff in every department of the club for their unwavering support in good times and bad.
"We won two trophies - achievements that I will cherish for the rest of my life. Of course, my dream was to bring more trophies to the cabinet. Unfortunately, that dream has come to an end.
"I wish all Manchester United fans nothing but success, trophies and glory. Your support and the warmth I received from everyone at the club helped me feel at home. Thank you for this chapter in my life. Erik"
Ten Hag was fired after Sunday's controversial 2-1 defeat at West Ham, which left United 14th in the standings with just three wins and 11 points after nine matches.
United have drawn all three of their Europa League games, with last Thursday's 1-1 scoreline at Fenerbahce meaning they have failed to win a European match in a year.
Interim boss Ruud van Nistelrooy oversaw a 5-2 Carabao Cup win against Leicester on Wednesday and is now preparing to lead the side in Sunday's league game against Chelsea.
The Dutchman, formerly assistant to compatriot Ten Hag, will also take the side against PAOK in the Europa League and Leicester again in the Premier League before handing the reins to Amorim, who starts work at Old Trafford on Monday 11 November.
