Ange Postecoglou has been sacked by Nottingham Forest - just 39 days and eight winless games since he was appointed manager.
Forest lost 3-0 to Chelsea on Saturday lunchtime, their sixth defeat in his short reign which left them 17th in the Premier League table.
The club have not won since the opening match of the season, under Nuno Espirito Santo, who was shown the door two games later.
In a short statement released just 19 minutes after full-time of the Chelsea loss, Forest said: '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.
'The club will make no further comment at this time.'
Postecoglou's sacking after 39 days means he takes the unfortunate accolade of having the shortest reign of any permanent Premier League boss to leave a club during a season.
Ange Postecoglou has been sacked as Nottingham Forest manager after just 39 days
Forest lost six of the Australian's eight games in charge after he replaced Nuno Espirito Santo
The 3-0 home defeat by Chelsea on Saturday proved to be the final straw for Postecoglou
Postecoglou tried to implement a more attacking style of play than under Nuno, but his tenure began with defeat at Arsenal followed by an embarrassing 3-2 Carabao Cup defeat at Swansea, where they threw away a two-goal lead.
This month's Europa League defeat by Midtjylland at the City Ground, in front of owner Evangelos Marinakis, saw the home crowd turn on Postecoglou and - following defeats at Newcastle and now Chelsea - Marinakis has now wielded the axe.
The writing appeared to be on the wall when reports broke last week that replacements had been sounded out by the Forest owner.
Postecoglou also revealed pre-match that he didn't hold talks with Marinakis over the international break, despite saying he expected to do so after their loss by Newcastle.
Marinakis then left his seat at the City Ground midway through the second half of the Chelsea defeat with his side 2-0 down at the time.
Postecoglou was sacked by Tottenham despite leading the club to the Europa League title, as Spurs bosses deemed the club’s 17th-placed finish in the Premier League unacceptable.
The 60-year-old’s main brief at Forest was to win a second straight Europa League title, as that would secure a place in next season’s Champions League.
On Friday Postecoglou had launched an impassioned defence of his position, saying: 'I guess from my perspective, I just don't fit. Not here. Just in general. If you look at it through the prism of: I'm a failed manager who is lucky to get this job - I know you're smirking at me and that's what's being said and I can find the print where that's being said - then of course it looks like this manager is under pressure.
Before the end of the Chelsea game, owner Evangelos Marinakis decided to leave his seat
The embarrassing defeat at Swansea - where Forest had led 2-0 - was an early sign of trouble
Fans turned on Postecoglou after defeat by Midtjyyland in the Europa League this month
'I took over Spurs, who finished eighth. No European football. Massive club who can't have two years without European football. We finished fifth in my first year. And every time Harry Kane scores a goal, I wish he'd just stayed one more year. It would have been handy to have him after finishing fifth.'
Postecoglou continued: 'But somehow that year has disappeared from the record books. In fact, it was used as a reason for me losing my job because even Tottenham decided to exclude the first 10 games because they were an anomaly apparently. Although the first 10 games here are very important, apparently.
'We finished fifth, I got them back into European football where Tottenham should be. I was in meetings and people still at that club were in those meetings where I was told winning a trophy is everything for a football club. That's fine.
'We win a trophy. We shed the tag of being 'Spursy'. It's Champions League football, which brings some rewards, the opportunity to bring in better players. But all I've heard since I finished at Tottenham is I finished 17th last year.
'Maybe I'm a manager where if given time, the story always ends the same. At all my previous clubs it ends the same: me with a trophy.'
But Forest - who are likely to go for a replacement with a more conservative style of play - have been unwilling to wait for that to play out.