Luiz Felipe Scolari needs more time to make his mark at Chelsea because of the "big personalities" in the dressing room, says his close friend Leonardo.
Pressure has mounted on the Blues boss following his side's 3-0 capitulation against Manchester United on Sunday.
Leonardo, who played under Scolari for Brazil, told BBC Sport: "We are talking about five months since he took over.
"Chelsea are a team with big, big personalities and it's not always easy to make your points of view."
Sunday's defeat left Chelsea four points behind Premier League leaders Liverpool and only one ahead of United, who have two games in hand on their rivals.
The result also continued Scolari's miserable league record against the other members of the 'Big Four'.
In their four matches against United, Arsenal and Liverpool this season, Chelsea have gained only one point. Mourinho is a very important coach and Scolari has a different style, but there is more than one way to win
Leonardo on Mourinho
But Leonardo, who is the technical director at AC Milan, said: "You need time to instil your philosophy and system on a new side and to change players.
"For the last five years Chelsea have played the same way and it takes time to change that.
"You also have to remember that Manchester United are probably the best team in the world at the moment and it's not easy to play against them.
"The important thing now is for the club to be behind the manager. You always need the club to support you and give you the conditions to do well."
Leonardo, who describes Scolari as his "big father", believes the pressure the Brazilian is currently under will make him "stronger than ever".
"When he has a difficult situation he always finds a way to resolve it," stated Leonardo.
"He is stronger in those moments and I believe he can change the situation very, very fast.
"He is a motivator and the relationships he develops with his players are always very strong.
"He has adapted himself in many different situations. Being the coach of Portugal or Brazil was not always easy and the pressure was often intense."
Leonardo also dismissed the theory that Scolari would struggle to win over fans and players used to success under his predecessor at Stamford Bridge Jose Mourinho, who is now the manager of Inter Milan.
"Mourinho is a very important coach and Scolari has a different style and approach but there is more than one way to win. Both men have been very successful in their careers. "Scolari will do very well in England and do very important things at Chelsea."