Former Chelsea sporting director Frank Arnesen believes Jose Mourinho was too demanding of his players as the team could not cope with the Portuguese's intensity.
Mourinho guided Chelsea to the Premier League title and League Cup in 2014-15, but was eventually fired in December last year after a dismal start to this season.
On Monday, midfielder Cesc Fabregas stated that Mourinho gave the players extra time off following their title win, and the Spaniard felt he and his team-mates had let the manager down in their defence of the crown.
But Arnesen believes Mourinho's methods were ultimately what cost him his position at Stamford Bridge.
"Mourinho is very demanding and sometimes the players can't take it," Arnesen told Omnisport.
"He made some drastic changes and it cost him."
Mourinho eventually made way for caretaker boss Guus Hiddink, who will be replaced by Antonio Conte come the end of the season and Arnesen has high hopes the former Juventus coach will succeed.
"Conte has the winning mentality in his blood," Arnesen added. "He is disciplined and tactically very strong.
"But we don't know how he will deal with the pressure at Chelsea."
Mourinho remains a free agent following his Chelsea departure and has been heavily linked with a move to Manchester United, with current boss Louis van Gaal under heavy pressure.
Nevertheless, Arnesen has urged the Old Trafford side to stick with the Dutchman.
"Van Gaal could not buy all his players, but he has done tremendously well with the young kids," Arnesen stressed.
"Manchester United should give him at least one year more.
"What would happen if they replaced Van Gaal with Mourinho? The philosophy of Manchester United will go out of the window. But maybe they are that keen to have success..."
Arnesen worked at Tottenham in 2004-05 before leaving the club for Chelsea and he is impressed by Spurs' performances this campaign, even though he thinks it would be an even bigger achievement if Leicester City were to win the title.
"Tottenham? I'm surprised," the Dane continued. "The coach has done fantastic work, [Mauricio] Pochettino is very demanding. [Christian] Eriksen told me he has never been so tired in his life.
"A title would be a fantastic achievement for Spurs. Leicester are the story of the century."