Middlesbrough chairman Steve Gibson says he decided to sack manager Gareth Southgate several weeks ago.
Gibson said the club's long-term future was a key factor and that Tuesday's 2-0 win over Derby made no difference.
"I made the decision two or three weeks ago, but you have to act in the best interests of your football club," Gibson told BBC Tees.
"We felt that the time had come to make changes to the running of our football club," he added.
"At the beginning of the season I made it absolutely clear we had one objection - promotion at the first attempt, preferably in an automatic promotion spot rather than the lottery of the play-offs," he added.
But with recent results going against Southgate, Gibson said he felt forced to act.
"After the result against Leicester and leading up to that I began to feel uncomfortable with the situation," he continued.
"The best interests of the football club was to have a strategy I was clear about and a strategy that I could implement on a reasonable timescale.
"One result against Derby County at home wasn't going to change any of that. Part of the strategy was to relieve Gareth of his responsibilities and duties no matter what after the game last night."
Boro hope to name Southgate's successor by this weekend, with Gibson saying: "I expect us to be able to make an announcement before the Preston game [on Saturday]."
Among the favourites to replace Southgate is former Celtic boss Gordon Strachan, who has been out of work since leaving the SPL side in May, while other names linked are Leicester City manager Nigel Pearson and former Newcastle and Blackburn manager Graeme Souness.
Southgate's departure comes with Middlesbrough fourth in the Championship after 13 games, just a point behind leaders West Brom.
However, with three defeats at home already this season, the latest of which came against Watford on Saturday, Gibson admitted that the long-term ambitions of the club had to take priority over short-term form.
"I think the league position flatters some of our performances. When I look at some of the important games we've played against the clubs who are close to us we have quite an abysmal record."
"In football terms, it wasn't that tough a decision. In personal terms, it was very difficult because Gareth Southgate is a very good and decent man," Gibson added.
"The blame traditionally lies at the manager's door and we needed to spark things, and get the fans and the town back behind the club. We can't afford the splinters we have."
But Gibson played down claims that falling attendances were at the heart of the dismissal.
"I don't know where this story started. A lot of the factors are totally outside the manager's control," he explained.
"Falling attendances is not the story, the story is about how the fans feel about the club, their disenchantment over the last 12 months and their lack of faith that the club can get back into the Premiership."
Gibson has been involved with Middlesbrough since joining the board of directors aged 26, and was a founder of the consortium that brought the club out of liquidation in 1986.
He has been chairman since 1994, and has overseen a spell which has included an FA Cup final appearance, three League Cup finals, including a win, and a Uefa Cup final for the Teessiders.
Meanwhile, Leicester chairman Milan Mandaric does not expect his manager Pearson to move to the Riverside.
He told BBC Radio Leicester: "There is constant dialogue with Nigel. Nigel is here to stay. He is happy with the club and the club are happy with him and there is no reason why we shouldn't keep him long term.
"Nigel is very solid. He is honest. I don't believe he will move. He is a very stable guy and I wouldn't be worried about Middlesbrough at all.
"It would always be nice to hear from Steve [Gibson]; we are good friends. But I don't think I would welcome that conversation about Nigel.
"But in all fairness if people were not interested in Nigel I would be worried as well. I don't believe Nigel would want to go. I find it difficult to believe that Nigel would want to leave this club.
"He's a young man, a good man and I will do all I can to give support to Nigel to stay here."
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