Garry Monk says he was "surprised" by Middlesbrough's decision to remove him as manager following their victory at Sheffield Wednesday on Saturday.
The former Swansea and Leeds boss left hours after the 2-1 win, with Boro ninth in the Championship.
He has since been succeeded by ex-Stoke and West Brom manager Tony Pulis.
"The feeling amongst everyone in the dressing room after Saturday's game was that it was the turning point in our season," Monk said.
In a statement via the League Managers' Association, he added: "Just hours earlier we had enjoyed what we felt was the side's best away performance of the season in our win against Sheffield Wednesday.
"My staff and I were surprised by the timing of the decision."
- Middlesbrough part company with Monk
- Pulis appointed new Boro manager
- New Boro boss Pulis hopes to repeat Stoke success
Monk, 38, took over at the Riverside in June after leaving Leeds and was tasked with leading the side back to the Premier League following relegation last season.
He left Boro three points adrift of the play-off places after a summer transfer window which saw them spend £15m on striker Britt Assombalonga from Nottingham Forest, bring in fellow forwards Ashley Fletcher and Martin Braithwaite, and goalkeeper Darren Randolph.
"Of course, we expected to be higher up the league and to be seeing more consistent performances by this stage. I do accept my responsibility for that," he said.
"We were all really confident that we could still achieve the target of promotion to the Premier League, which was set at the start of the season.
"I really hope that the club can now keep moving up the league."