Porto won the second of their two European Cups under Jose Mourinho in 2004, and were crowned Europa League champions in 2011 under Andre Villas-Boas, while their opponents Malaga are playing in their maiden Champions League campaign.
But Malaga have made it to the last 16 unbeaten in the competition, and Pereira knows his side will be up against it in the tie.
"If we were playing in the past, the victory would be guaranteed for Porto, but it is about these teams now," he said ahead of the first leg at the Estadio do Dragao.
"Malaga are fourth in the league, they beat Milan in the group stages, they have proved their quality.
"Although they have players who stand out and have the capacity to decide a game, I admire Malaga as a team."
The modern Malaga are a club of contradictions at present, catapulted into Europe's premier competition on the back of major investment but now battling severe financial problems as some of the bills become due.
Last month they tied down star playmaker Isco to a new long-term contract with a hefty release clause, but the 20-year-old has admitted he could still find himself on the move soon as Malaga may choose to cash in.
"I am not afraid, because my head is focused here," he told AS. "Any club who pays that much money will surely be a big club.
"Then, if it is to help Malaga, I would not have a problem accepting a departure which would be good for everyone."
Malaga have already seen Santi Cazorla and Nacho Monreal depart for Arsenal in the past two transfer windows to help ease financial concerns.
The loss of Monreal has added to Manuel Pellegrini's main headache ahead of this match with neither of his current first-choice full-backs - Eliseu and Jesus Gamez - available, although Martin Demichelis could return to strengthen the middle of the park.
In a show of unity, Malaga have flown their entire squad, including those not registered for the Champions League, to Portugal to be part of their preparations.
Pereira offered no clues as to whether or not James Rodriguez would return for this match as had been expected, having missed the last seven outings with a thigh problem.