Leeds United fired manager Marcelo Bielsa on Sunday after a string of poor results left the Premier League club just three points above the relegation zone.
The 4-0 loss to Tottenham at Elland Road on Saturday was their fourth straight defeat in five games, during which they conceded 20 goals and fell into the Premier League relegation zone.
After the Spurs defeat, the 66-year-old remained confident he could turn things around, but the Leeds board decided otherwise.
"Leeds United can today confirm the club have parted company with head coach Marcelo Bielsa," a club statement said.
Leeds chairman Andrea Radrizzani said: "This has been the toughest decision I have had to make during my tenure at Leeds United, taking into account all the success Marcelo has had at the club."
He added: "With Marcelo as our head coach, we had three incredible campaigns and the good times returned to Elland Road. He changed the culture of the club and brought a winning mentality to us all."
“The moments created, particularly in the 2019/20 season and winning promotion to the Premier League, will of course live long in all our memories, myself and the fans included.
“However, I have to act in the best interest of the club and I believe a change is required now in order to secure our Premier League status. Recent results and performances have not met our expectations.
“We find ourselves in a precarious league position and I feel now is the right time to bring in a new head coach, in order to have an impact in the decisive stage of the season.
“Naturally, myself, along with everyone else at the club would like to thank Marcelo for his efforts and achievements and we wish him the very best for the future.”
Bielsa took over the club in June 2018 and in his second season ended a 16-year wait for the Premier League to return.
But her second season in the top flight has been marred by injuries and growing questions about Bielsa's tactics.
Leeds said the club intends to announce Bielsa's replacement on Monday.
Former RB Leipzig and RB Salzburg boss Jesse Marsch is a favorite to take over.
Marsch, 48, was closely linked to the Elland Road takeover. He has been out of a job since briefly leaving Bundesliga side RB Leipzig last year, but he is best known for his work with Red Bull New York and Red Bull Salzburg.
Director of football Victor Orta added: “Since arriving at Leeds United Marcelo had a huge impact on the club, on a scale I have not seen before.
“He has created a legacy, overseeing major infrastructure improvements at Thorp Arch, uniting the supporters and the players, and giving a clear pathway for young players to transition into the first team.
“It is disappointing his reign has had to end in this manner, given the special times we have enjoyed in recent years, which have been some of the best in my career, but we cannot hide from recent results.
“I would like to thank Marcelo for his commitment and dedication, and I wish him every success going forwards.”