Xisco Munoz admitted he did not expect his sacking by Watford after becoming the first managerial casualty of the Premier League season on Sunday following a poor start to the campaign.
Watford fired the Spaniard after seven games with a club statement saying recent results "strongly indicate a negative trend at a time when team cohesion should be visibly improving".
Saturday's 1-0 defeat at Leeds left the club with seven points from a possible 21. After Sunday's results they were 15th in the table.
Munoz took charge at Vicarage Road in December and successfully guided the club back to the top flight with a second-placed finish in the Championship last season.
The club statement added: "The Hornets will always be grateful to Xisco for the part he played in securing last season's promotion and wish him well for his future career in football."
His departure means Watford are now looking for a 17th new manager in just over 10 years.
Munoz expressed his surprise at his dismissal on his personal Twitter account.
"It's been a wonderful journey and it concluded in a way that I neither expected or wished for," he said.
"I'm grateful and I will only remember all the good things I have experienced.
"It's a sad day for me and my family because it marks the end of a period at a club and in a city where we have felt at home.
"I've got nothing but words of gratitude for the club that gave me the opportunity to start my first adventure in this exciting country."