Captain Roman Weidenfeller has insisted Borussia Dortmund convert their chances against Napoli on Tuesday in a must-win game as last season's Champions League finalists face a group-stage exit.
Dortmund's 1-0 defeat at home to Arsenal three weeks ago left them third in Group F on six points, three behind joint leaders Napoli and the Gunners and heading for the Europa League.
Both Napoli and Dortmund come into their penultimate group stage game after suffering defeats in their respective leagues.
Borussia have lost their last three games in all competitions, including Saturday's comprehensive 3-0 home defeat to Bayern Munich in a repeat of May's Champions League final.
A fourth straight defeat would further erode confidence and, if Arsenal only draw with Marseille in London, end their Champions League's knock-out stages ahead of their final match at Marseille on December 11.
Dortmund now find themselves seven points adrift of Bayern in the Bundesliga and Weidenfeller has said his team must improve their finishing and take their chances against Rafael Benitez's Napoli.
"I think Tuesday's game is much more important than (the defeat to) Bayern," said Weidenfeller, who was sent off in Dortmund's 2-1 defeat at Napoli in September.
"We have to win against Napoli at home, it's as simple as that.
"As I have been saying for a few weeks now, there is a lack of single-mindedness and determination with us at the moment
"Our problem is that we are not finishing our chances.
"There are too many times when we play the ball across the penalty area and don't go directly for goal.
"We have to take our chances, because football is decided by goals and at the moment, we're not scoring them."
Dortmund's star-studded attack were left frustrated by Bayern's defence as both attacking midfielders Henrikh Mkhitaryan and Marco Reus squandered clear chances.
Jurgen Klopp's Dortmund have only scored one goal in their last three games and to make matters worse, they have lost their entire back four in recent weeks.
Both Mats Hummels and Marcel Schmelzer returned from international duty with Germany carrying leg injuries and new-signing Manuel Friedrich was thrown in at centre back alongside Greece's Sokratis.
A second defeat in four days would put a significant dent in Dortmund's ambitions, but Weidenfeller insisted there is still all to play for.
"Nothing is decided yet. Neither in the Champions League or in the Bundesliga," he said.
"We can't just assume that we'll be German champions again after a year's break (when Bayern were Bundesliga winners last season).
"We're seven points behind Bayern, but the season is still long enough."
Napoli only need to avoid defeat at the Westfalenstadion to seal progress to the knock-out stages.
They will be without playmaker Marek Hamsik, who suffered a foot injury during Saturday's shock 1-0 defeat to Parma.
The Slovakia international is likely to be replaced by Lorenzo Insigne, who normally operates on the left, or versatile Belgian Dries Mertens.
Benitez has said he expects a much better performance in Germany with the prize of a place in the knock-out stage at stake.
"Tonight we played badly, especially in attack. In the end, we didn't execute the plan we'd made for this game," he said after the Parma defeat.
"Now we have to turn our focus to Dortmund, we'll be looking to recharge our physical and mental batteries for a match which is crucial to us.
"I'm sure the urgency of the game will give the lads the required incentive."