Jose Mourinho has left his job as Manchester United manager after two and a half years in charge.
The Portuguese, 55, won the League Cup and the Europa League at Old Trafford.
But United are sixth in the Premier League, 19 points behind leaders Liverpool, who beat them 3-1 on Sunday.
“A caretaker-manager will be appointed until the end of the season while the club conducts a thorough recruitment process for a new, full-time manager,” United said in a statement.
“The club would like to thank Jose for his work during his time at Manchester United and to wish him success in the future.”
United’s haul of 26 points after their first 17 Premier League games, is their worst tally in the top flight at this stage since 1990-91.
They are 11 points off the top four and closer to the relegation zone than the top of the table.
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The decision to sack Mourinho, which will cost more than £18m, has been taken in the long-term interests of United with a view that the club is bigger than any one individual.
Mourinho is understood to have wanted his own structure, but the new manager will be appointed with a head of football above him reporting to executive vice-chairman Ed Woodward.
A United statement said: “A caretaker manager will be appointed until the end of the season while the club conducts a thorough recruitment process for a new, full-time manager.
“The club would like to thank Jose for his work during his time at Manchester United and to wish him success in the future.”
The club hope to appoint a caretaker manager before they face Cardiff City on 22 December but it will not be assistant manager Michael Carrick or academy boss Nicky Butt.
The candidate will be drawn from outside the club, but will not be former Arsenal boss Arsene Wenger.
A familiar conclusion to a rocky season
United’s haul of 26 points after their first 17 Premier League games is their worst tally at this stage of a season since 1990-91.
They are 11 points off the top four, which would earn a Champions League qualification place.
The sacking of Mourinho, who replaced Louis van Gaal in May 2016 and signed a contract extension in January, comes after a fall-out with £89m record signing Paul Pogba, who was an unused substitute for the defeat at Anfield on Sunday.
Following a 1-1 draw with Wolves, Pogba said he wanted United to be able to “attack, attack, attack” at home, which led Mourinho to say the France midfielder would no longer be the club’s “second captain”.
After Mourinho was sacked, a post which said “caption this”, along with a knowing expression on Pogba’s face, appeared on his Twitter account before being deleted.