Former Chelsea boss Avram Grant says Andre Villas-Boas will be expected to achieve immediate success at Stamford Bridge.
The 33-year-old tactician was unveiled as manager on a three-year deal on Wednesday.
Grant, who took over from Jose Mourinho in September 2007, led Chelsea to the 2008 UEFA Champions League final, which they lost to Manchester United, and second in the English Premier League.
The Israeli said Villas-Boas would need to be successful early on to ensure pressure would not build on him.
Owner Roman Abramovich is a guy who wants results and will support you financially, Grant told Radio 5 Live on Thursday.
He has invested a lot of money and wants success as early as possible.
The former Porto manager led them to league glory and the Europa League crown, having worked under Mourinho at the Portuguese club, Chelsea and Inter Milan.
Grant said Villas-Boas age should not be a factor given his ability.
I liked him a lot when I was director (of football) of Chelsea and he was a scout. He s a nice guy, nice person and I enjoyed being with him, he said.
I know he s young but fellow coach Pep Guardiola was young when he started at Barcelona and without much experience and did a great job. Experience is important but quality and authority is more important.
Andre did a great job at Porto. The players liked him. Players are human beings. If they see he has the quality then they will support him.
Villas-Boas first game in charge will be a pre-season friendly against Dutch side Vitesse on July 9.
