The Dragons took the lead early on at Estadio da Luz through a thunderbolt by Brazilian forward Hulk. Benfica responded with two goals from Oscar Cardozo, but after the break James Rodriguez and Maicon netted for the visitors, while the Eagles had Emerson sent off.
"These are three points, there are still many matches left and we are going to have to work hard to achieve our goal which is the title," said Pereira at the post-match press conference.
"Nothing was decided today, the difference between the two clubs in the table is very small. This was a good, morale-boosting victory.
"Porto went into this match with the clear goal of getting the three points."
Following Friday's victory, Porto are first in the Portuguese league standings with 52 points, three ahead of Benfica.
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