Mick McCarthy has announced his departure from Ipswich Town with immediate effect following Tuesday's 1-0 win over Barnsley.
The 59-year-old was due to leave the Championship club at the end of the season, but departed four games early, alongside assistant Terry Connor.
McCarthy was asked in his post-match news conference about fans' negative reaction to debutant Barry Cotter being substituted.
"I won't have to listen to that again, that's my last game," McCarthy replied. "I'm out of here."
The news was confirmed on the official website as the veteran coach said: "I spoke with Marcus (Evans, owner) at the weekend and we agreed that it was in the best interests for me, the players and the club that I move on now.
"I said I would see the season out but it's been a new experience and it's not one I have been enjoying to be honest. I have continued to do my job to the best of my ability but there is something missing and I'm not comfortable with that.
"I have had a great time here and worked with some great people and to all those who have given me wonderful support over the last five and a half years - and there are many - I want to put on record my personal thanks.
"The players here can look forward to a new challenge with whoever comes in and I want to wish them, the staff and the club the best of fortunes. I'll also be looking forward to a new challenge elsewhere. I've still got a lot of football in me."
Ipswich head of coaching and player development Bryan Klug has taken interim charge with the team 12th in the Championship, ahead of their trip to Nottingham Forest on Saturday.