The Tottenham Hotspur Supporters' Trust (THST) has thanked Mauricio Pochettino following his sacking, while questioning the timing of the decision.
Pochettino was dismissed from his role on Tuesday, leaving Spurs after more than five years in charge, during which he led the club in title challenges and a run to the 2018-19 Champions League final.
Poor results at the start of this season, with Tottenham 14th after 12 matches, resulted in chairman Daniel Levy making the controversial call.
But the THST is not convinced and is worried by the timing of Pochettino's departure just four days before a London derby away at West Ham.
A THST statement read: "We're shocked and saddened to hear our club has sacked Mauricio Pochettino and his coaching staff.
"During his time at Spurs, Poch gave us many of our best moments as supporters, made Tottenham Hotspur a force to be reckoned with again, and forged a strong link with the fans. We will never forget the joy he brought us.
"Of course, results in the league have been disappointing for some time. But many fans thought Poch had earned the right to turn it around in the first sustained period of poor form we've had during his time at the club.
"We now have to look forward and take stock. But there are questions that must be asked of the board.
"The club's statement makes it clear the board has decided to sack the manager and coaching staff. It is their decision.
"We question why this decision was taken at the end, rather than the beginning, of the international break. We question whether the timing of the decision leaves the club with much choice in who takes over.
"To take the decision it has, the board must have a clear plan for what and who comes next. It needs to tell this club's supporters what that plan is.
"And the board also needs to consider its own role in this.
"Is the manager solely accountable? How much has the board's line on wages and transfers contributed to player unrest and disaffection? How much did it contribute to the situation we now find ourselves in? And will it change to help support a new manager?
"We'd like to put on record our thanks to Mauricio Pochettino, Jesus Perez, Toni Jiminez and Miguel D'Agostino for the fantastic football and magical moments they have brought us over the last five years."
Early reports suggest Jose Mourinho is the leading target for Tottenham and would be interested in the role despite his links to rivals Chelsea.