Pereira has been installed as Porto's new coach after Villas-Boas handed in his resignation earlier on Tuesday to become free to sign for Chelsea.
Porto's fans fear that the appointment of a coach without previous experience at a high level could prevent the club from emulating a season in which they managed to win four titles.
However, Pereira, who was Villas-Boas' assistant, has indicated there is still much work to do and has set sights on winning the domestic league.
"I want to thank the president and the board for the trust they have in me. I want to say that this club will continue winning," Pereira said at his official presentation.
"The likelihood that we will continue winning will be big. The team can still grow. Our goal is the league. That is how we started last season and that is how we are going to start the next one."