Porto coach Vitor Pereira admits Tuesday night's final make-or-break Champions Group G encounter at home to Zenit St Petersburg may be pivotal to their season.
The hosts have to win to ensure they do not fail to qualify for the knockout stage for the first time since 2005/2006.
And while Pereira's side 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.
"It is a very important game for the season," Pereira told his pre-match press conference,
"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."
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 in their first Champions League outing in mid-September.
