Nottingham Forest head coach Ange Postecoglou was sacked just 17 minutes after the side's 3-0 defeat by Chelsea at the City Ground on Saturday.
The Australian's dismissal - 39 days after his appointment on 9 September - means Postecoglou's stint at Forest is the shortest permanent managerial reign in Premier League history.
The former Tottenham boss failed to win any of his eight matches in charge of Forest, with two draws and six defeats across all competitions.
Forest collected just one point from Postecoglou's five Premier League matches in charge, leaving the side one point above the relegation zone in 17th.
"Nottingham Forest Football Club can confirm that after a series of disappointing results and performances, Ange Postecoglou has been relieved of his duties as head coach with immediate effect," a Forest statement read.
"The club will make no further comment at this time."
Postecoglou's 39 days in charge means he has broken Les Reed's record for the shortest reign - in terms of days in charge - of any permanent managerial appointment in Premier League history.
Reed spent 40 days in charge of Charlton Athletic in 2006 and was sacked having one just one of his eight matches in charge in all competitions.
Sam Allardyce, who managed 30 days in charge of Leeds United, was an interim appointment at Elland Road.
Former Crystal Palace boss Frank De Boer still holds the record for the fewest matches managed by a permanent appointment in the Premier League, having oversaw four games in charge at Selhurst Park.
Postecoglou managed Forest five times in the Premier League.
Postecoglou's departure means Forest are searching for their third manager already this season, having sacked Nuno Espirito Santo just three matches into the campaign.
On Forest's radar is Fulham head coach Marco Silva, with sources indicating the Portuguese is the preferred option of several internal figures at the City Ground.
Silva, who worked under owner Evangelos Marinakis at Olympiacos, has cemented Fulham's position in the Premier League by adopting the sort of football Forest believe can help stabilise them following their poor start to the season.
But Silva is under contract at Craven Cottage, with sources informing BBC Sport the 48-year-old has a "significant" release clause in his contract.
Having just paid off Nuno and with Postecoglou due compensation, there would be an obvious reluctance to fork out a further large sum to appoint Silva, particularly given he will be available for free when his contract expires at the end of the season.
Given the difficulties attached to attracting Silva, it is understood Forest have studied the merits and, more pertinently, potential costs of alternatives.
Sources have told BBC Sport that the prospect of reappointing Steve Cooper, who led Forest back to the top flight in 2022 before being sacked and replaced by Nuno in December 2023, has been considered.
But Cooper was recently appointed head coach of Danish club Brondby.
Another option explored, as reported by BBC Sport last week, is the appointment of Sean Dyche.
The attraction of the former Burnley and Everton head coach is clear - he has a proven track record in keeping teams in the Premier League, and his tactical approach is akin to the style Forest are targeting.
Dyche, who left Everton in January, also lives close to Nottingham and is available without the need to pay a release clause.
When Postecoglou arrived at the City Ground, Forest were 10th in the Premier League and on the cusp of playing in Europe for the first time in three decades.
Marinakis said Posetcoglou's experience at the "highest level" along with "his desire to build something special" made him a perfect fit for the club.
But it was far from a perfect start for Postecoglou, as Forest were beaten 3-0 away at Arsenal in his opening match.
A poor start was cemented when Forest were knocked out of the Carabao Cup by Swansea City, when they threw away a 2-0 lead in Wales.
Draws with Burnley in the Premier League and Real Betis in the Europa League did little to quieten a growing discontent.
The bubbling anger spilled over after a 3-2 defeat at home to Midtjylland in the Europa League, when a section of Forest supporters chanted "you're getting sacked in the morning" towards the former Celtic boss.
Postecoglou was defiant after a 2-0 defeat by Newcastle before the international break, saying: "I love a fight" in the face of questions about his job.
But a 3-0 defeat by Chelsea at home proved a defeat too far for Postecoglou, who has now been sacked twice in the last five months by Premier League clubs.
