Andre Villas-Boas's former assistant at Porto has said that the Chelsea boss needs time at Stamford Bridge.
The 34-year-old's future has been questioned after a poor first season in charge of the Premier League side.
"Andre is a quality coach and will certainly, in time, prove his quality and competence," said Vitor Pereira.
Villas-Boas and Periera won the quadruple with the Portuguese side last season.