Former England manager Steve McClaren was sacked Sunday by Derby County for the second time with the English second-tier side saying the club had lacked "focus, passion and commitment".
Friday's 3-0 defeat by Championship high-flyers Brighton left Derby 10 points adrift of the top six in the division and with little realistic hope of being promoted to the lucrative Premier League this season.
"Derby County has parted company with manager Steve McClaren with immediate effect," said a club statement.
Assistant manager Chris Powell and technical director Chris Evans have also left the club.
It is the second time McClaren has been sacked as Derby manager following his dismissal in May 2015.
The 55-year-old returned to Derby last year with the aim of stabilising the Midlands club's position after they had flirted with the relegation zone a few months earlier.
But the Derby statement added: "However, since the turn of the year we have experienced a significant, unexpected and persistent decline in results, team unity and morale."
Derby chairman Mel Morris added: "Steve is a great coach, we have very talented players and first class facilities but the heartbeat, commitment, focus and passion has been lacking something fundamental.
“The Brighton game on Friday night was so far from what we expect to see from those wearing a Derby County shirt....Players should wear the shirt with pride and share, espouse and exude the qualities and values we believe are important to the club, its supporters and the community."
McClaren made his initial coaching reputation as an assistant manager at Derby in the 1990s before carrying out a similar role under legendary Manchester United boss Alex Ferguson.
After a two-year spell in charge of Middlesbrough, McClaren was chosen to succeed Sven-Goran Eriksson as England manager in 2006.
But a year later he was sacked after a 3-2 defeat by Croatia at Wembley meant England failed to qualify for the Euro 2008 finals.
Photographs of McClaren standing on the Wembley touchline sheltering beneath an umbrella as it rained led to him being dubbed "the Wally with the Brolly".