Jaroslav Plasil insists Bordeaux must take advantage of Marseille's current Ligue 1 problems with victory in Saturday's clash between the teams.
Bordeaux are eighth after a run of just one win in their last eight matches.
However, Francis Gillot's team are still two points and two places better off than their opponents at the Stade Chaban Delmas.
And Czech midfielder Plasil does not want to contemplate a season without European football for Les Girondins.
He told L'Equipe: "I do not think about it yet. We have six games left and will try to finish as high as possible.
"For me, Bordeaux deserve to play in Europe. Even if we had a good run earlier this year, which allowed us to return to the top half, it's been a complicated season, like the previous one. It's a shame."
He continued: "Marseille is an important game in a season. They have fallen on hard times but they still had a good run in the Champions League and have just won the League Cup."
Gillot predicted a physical contest on his club's official website as he said: "Currently, we are on a bad run but it is obvious that if we win against Marseille, the public could be with us - but it will be a very complicated game to win.
"Marseille won't let matches go. They still have a lot of talent and good individuals.
"I think it will be a very physical. I saw them play against Caen and they deserved to win. There was a lot of physical impact."
The 1-1 draw against Caen last time out represented an 11th game without a win in the league for Marseille, who could be without Loic Remy.
The attacker injured an ankle in Wednesday's match at the Stade Velodrome, with Jordan Ayew expected to start on Saturday.