Manchester United sacked manager Michael Carrick on Thursday after their worst-ever start to a Premier League campaign, with USA boss Mauricio Pochettino widely tipped to replace him.
Former United captain Carrick led the team to an impressive third-place finish last season, but they have taken just eight points from 10 games in the current campaign and are in the relegation zone.
The club confirmed in a statement that it had parted ways with the 45-year-old, following mounting speculation he would be axed during the international break.
"After a disappointing start to the season, the club has come to the extremely difficult conclusion that a change is necessary in order to achieve our ambitions," United's statement said.
"Michael is, and always will be, a Manchester United legend. Just as he did as a player, he has conducted himself with the highest standards of dedication and professionalism throughout his time back with the club."
United said they intended to appoint a permanent successor "as quickly as possible".
Carrick impressed after taking over as interim boss following Ruben Amorim's acrimonious exit in January, leading United to Champions League qualification.
He was rewarded with a two-year permanent deal but, hampered by the club's underwhelming recruitment in the summer transfer window, his side have endured a steep decline this season.
Carrick has struggled to maintain discipline, dropping captain Bruno Fernandes after he criticised his manager's tactics following a 4-1 thrashing at Champions League debutants Como.
And defender Lisandro Martinez spoke out against the club's hierarchy over their lack of top-quality signings.
Carrick's final game in charge was a chaotic 4-4 draw against Aston Villa on Sunday, after which he stressed he would not walk away.
United, however, have decided to act in the hope of saving their season after a paltry three wins from 15 games in all competitions.
It is believed Carrick's future was decided on Wednesday during a meeting in Monaco involving co-owner Jim Ratcliffe, chief executive Omar Berrada and director of football Jason Wilcox.
Ex-Newcastle boss Eddie Howe and Julian Nagelsmann, most recently in charge of Germany, were touted as possible replacements but Pochettino has now emerged as the overwhelming favourite to succeed Carrick.
The Argentine has extensive experience of the Premier League following spells in charge of Southampton, Tottenham and Chelsea, and he also coached Paris Saint-Germain.
Pochettino signed a contract extension to remain with the USA through to the 2030 World Cup just three months ago.
But Sky Sports reported Wednesday that United have "reached a verbal agreement in principle" with Pochettino, who has been linked with a move to Old Trafford on several previous occasions, to become their new boss.
United defender Harry Maguire paid tribute to Carrick in an Instagram post which read: "Will always be a legend. Respect. Thank you."
Carrick, who won multiple trophies as a midfielder in the club's golden era under Alex Ferguson, is the seventh permanent manager to be dismissed by the club since the Scot retired in 2013.
The Manchester United Supporters' Trust (MUST) said Carrick's departure marked "another depressing moment", pinning the blame on majority owners the Glazer family and minority shareholder Ratcliffe, with the club yet to win a Premier League title since the end of the Ferguson era.
"The Glazers' debt-funded takeover continues to burden the club," MUST said in a statement. "When (Ratcliffe's) INEOS came in they promised sporting excellence, but yet with repeated changes in football leadership we have seen anything but.
"It is time for the owners to explain themselves and show some accountability."
United's next game is against fierce rivals Liverpool at Anfield on November 22.