Porto must beat Zenit St Petersburg at home to maintain their impressive record of reaching the Champions League knockout stages.
Pereira aware of importance of beating Russian side
Porto must beat Zenit St Petersburg at home on Tuesday night to maintain their impressive record of reaching the UEFA Champions League knockout stages.
Vitor Pereira's side have endured a mixed group campaign, but have not failed to advance from this round since the 2005/06 season.
And, while Porto may be top of their domestic league on goal difference from Benfica, their position is not as strong as it has been.
Porto have dropped six points in 11 league matches - as many as they did in the whole of last season - and their coach is conscious of the potential effects an early exit from the Champions League could have.
Complicated
"It is a very important game for the season," said Pereira. "But in terms of my career this is just a game, there will be others more important.
"We know what we want and we want to continue in the Champions League.
"For this we have to overcome this obstacle against a very difficult Zenit side. Zenit are a complicated team, with great performers.
"They have an Italian style as the team defend well but like to attack with a lot of people and stretch play over the whole field.
"But we know the values that this club stands for. Based on the competence, responsibility and team spirit we have enough to beat Zenit."
Porto will be without Fredy Guarin due to a calf injury, while Nicolas Otamendi, Alvaro Pereira and James Rodríguez are one booking from a suspension.
Second-placed Zenit arrive in Portugal requiring only a point to secure their maiden appearance in the last 16 of European's premier club competition.
Luciano Spalletti's side are currently on a 14-match unbeaten run in all competitions, recording eight victories since losing to Group G leaders APOEL Nicosia in their first Champions League outing in mid-September.
Striker Aleksandr Kerzhakov has been absent with an ankle injury for the past two months, while Domenico Criscito and Tomas Hubocan are a yellow card away from a ban.
