Slaven Bilic insists he is leaving West Ham with his "head held high" after he was sacked with the club languishing in the bottom three.
Saturday's 4-1 home defeat by Liverpool was the final straw for the Hammers hierarchy, who axed Bilic with just over six months of his three-year contract remaining.
Former Everton and Sunderland boss David Moyes is anticipated to be named as his successor, and could be appointed as early as Tuesday.
Bilic guided West Ham to seventh in his first season - the club's last at Upton Park - and despite a tough maiden campaign at the London Stadium they rallied to finish 11th.
But the Hammers have won just two league matches this season, against Huddersfield and Swansea, having begun the campaign with three successive defeats - shipping 10 goals in the process.
And Bilic admitted he understood joint-chairmen David Sullivan and David Gold's "desire to make a change" as they bid to guide West Ham away from the foot of the table.
"I am sad that it hasn't worked out in the way we wanted this season," Bilic said in a statement on the club's website.
"But I leave with my head held high, along with some wonderful memories that I will always cherish.
"I was confident that we would be able to progress this season and continue to close the gap between expectation levels and reality, but unfortunately it has not been the case.
"I believe in my qualities and wanted desperately to fight on to turn things around, but I understand the club's desire to make a change."
Sullivan and Gold will hope Moyes can shore up a leaky defence and maybe get a tune out of big-money summer signings Marko Arnautovic and Javier Hernandez.
Club-record capture Arnautovic has been such a disappointment he was booed off during the recent home defeat by Brighton.
In a joint statement on the club's website Sullivan and Gold said the decision to sack Bilic had been made with "heavy hearts".
They added: "During the summer, the board invested heavily signing the players Slaven believed would complete the squad he needed to push the club back towards the level we had reached in his first season, and we believe we have the players capable of doing that.
"We have not seen enough indication of the required improvement to give us the encouragement that things would change and we would meet our Premier League aspirations this season.
"We believe a change is now necessary to ensure we can begin to move the team back in the right direction."
Bilic's assistants Nikola Jurcevic, Edin Terzic, Julian Dicks and Miljenko Rak have also left the club.
Goalkeeping coach Chris Woods, who worked with Moyes at Everton and Manchester United, is the only member of the coaching staff who still appears under 'staff' on the club website.
Yet Bilic leaves West Ham as statistically their most successful Premier League manager.
The Croatian recorded a better points-per-game ratio (1.33) than any of his predecessors in the Premier League era.