Everton have sacked manager Ronald Koeman after Sunday’s 5-2 home defeat by Arsenal left them in the Premier League relegation zone.
A statement said the club “would like to express their gratitude to Ronald for the service he has given to the club over the past 16 months”.
The Toffees are 18th in the Premier League and have won just two of their nine league games this season.
“I still believe I can change the whole situation,” Koeman had said on Sunday.
Koeman became the third Premier League managerial casualty of the season after Frank de Boer left Crystal Palace and Craig Shakespeare was sacked by Leicester.
The 54-year-old Dutchman, who guided Everton to seventh place in his first season in charge last term, paid the price for a poor start to this season despite having spent £140m in the summer.
Everton’s majority shareholder Farhad Moshiri gave Koeman his backing a fortnight ago after their 1-0 defeat by Burnley, but the Toffees then drew at Brighton and lost to Lyon, in the Europa League, before their Goodison Park humbling by Arsenal.
Everton’s chances of progressing from Europa League Group E are slim, with the Merseysiders bottom after defeats by Atalanta and Lyon and a draw with Apollon Limassol.
On Sunday Koeman tweeted that getting a result against Arsenal was “impossible” after being reduced to 10 men while losing 2-1.
Koeman reported for training at the club’s Finch Farm base on Monday morning, with preparations for Wednesday’s Carabao Cup game at Chelsea seemingly under way.
But chairman Bill Kenwright and chief executive Robert Elstone were later reported to have arrived unexpectedly and Koeman’s dismissal was confirmed soon after.
Koeman’s assistant and brother Erwin will also leave the club along with his technical team – fitness coach Jan Kluitenberg and goalkeeping coach Patrick Lodewijks.