Carlo Cudicini believes Chelsea made a mistake by appointing Luiz Felipe Scolari as manager.
Scolari was named as Avram Grant's successor last summer and the Blues made an encouraging start to the season as they set the pace in the Premier League title race alongside Liverpool.
However, they struggled to sustain their challenge and Scolari was dismissed on Monday following a disappointing couple of months.
Cudicini, who was allowed to join Tottenham in last month's transfer window, does not feel Scolari was suited to a role in English club management.
"It just didn't work out," the Italian told the Sunday Times.
"I didn't say he was the wrong man the day he was appointed because I didn't know him then but now I know he was a mistake.
"He had been an international coach, not a club manager, for far too long.
"It was a different culture for him too. English football is totally different to what he knew and he found it difficult to adapt to the style and speed of the game.
"He was a very nice guy but not the right person."
Jose Mourinho won two Premier League titles with Chelsea and Cudicini admits he was able to adjust to the demands of English football much quicker than Scolari.
Comparing the two managers, Cudicini added: "Jose adapted very well to English football straight away.
"As soon as he arrived he seemed to know the players and what was required - the mentality, the way to train, everything.
"Scolari just didn't have the same impact."