Sam Allardyce believes Crystal Palace supporters will find out what boss Frank De Boer is made of this weekend.
De Boer has been told he must win at Burnley on Sunday, if he is to keep his job at Selhurst Park.
The Dutchman succeeded Allardyce in the summer, when Big Sam quit in May for health reasons, after saving the club from relegation.
Allardyce said: “Time is ticking for anybody that comes into the Premier League and doesn’t start as you’d expect.
“It’s a big introduction for him and you’ll see his worth now. You come to your best as a manager when you are in difficult positions.
“If you are a good manager, you will accept the pressures that come with it and deliver. You have to deliver as quickly as you possibly can to get the right result, otherwise you end up losing your job.”
De Boer arrived with a brief to improve the style of play at the club and inspired confidence the south Londoners would have a more productive campaign this time.
But the Palace players have been unimpressed by his methods and the club have been beaten in their first three matches.
Eagles chairman Steve Parish has held talks with De Boer, while the club have paid £26million for defender Mamadou Sakho, key to their survival last season while on loan from Liverpool.
Allardyce fears the speculation over De Boer’s future could prove counterproductive to the club’s cause.
He told talkSport: “To have the threat of win or be sacked – I don’t know if that is the case or not – adds to all the pressure, not just with him but, more importantly, the players.”
Allardyce believes 27-year-old Sakho will prove as crucial for De Boer as he proved during his own time at the club.
He added: “The main problem – which was the same thing that happened to me when I got there – is defending. Mama Sakho will hopefully cure that problem.
“He could be the saviour, as he was for me. He was one of the reasons we stayed up.”
De Boer’s agent claims the Dutchman’s loyalty to Ajax stopped him getting a job with bigger clubs than Palace. De Boer left Ajax in June last year after six seasons, which started with four consecutive Dutch titles.
And Guido Albers said: “I was called by top clubs from the Premier League, whether that was Tottenham or Liverpool, because he was successful at the time.
“Frank should have left sooner but he was loyal to Ajax.”