The Bayern Munich players received a stern warning from Uli Hoeness after they were roundly beaten 2-0 by Arsenal in the Champions League but managed to scrape through to the last eight.
The Bavarians, runaway leaders in the Bundesliga and favourites to lift the German Cup, played arguably their worst game of the season in front of a home crowd and toyed with elimination as the Gunners unsuccessfully tried to overturn the 3-1 deficit from the first leg in London.
"We have been playing disastrous football in the last three weeks," Hoeness said. "If the team draws the right conclusions from this game then it is still five minutes to 12. But we will not be able to win anything in the Champions League playing like that.
"If we keep on playing like we did against Arsenal then we will not beat anyone."
At first glance Hoeness' anger may look out of place for a team challenging for three trophies, having conceded just 10 goals in 25 Bundesliga games and having carved out a huge 20-point lead at the top with only one league defeat.
But a closer look at their Champions League performance this season reveals they have been far less effective there.
As opposed to the Bundesliga, Bayern have kept only one clean sheet in the Champions League so far while also losing twice as many matches than in the league.
While the Champions League is obviously a tougher competition, the Bavarians have had a relatively easy ride in the group stage.
They faced teams such as BATE Borisov - to whom they lost - and Lille, neither a European heavyweight.
Wednesday's game was also the first of 37 matches in all competitions where Bayern failed to score.
"We must be glad to have made it through and now we need to be careful," said Hoeness. "For me this was a well-timed warning shot."
Bayern are desperate for titles after two seasons playing second fiddle behind champions Borussia Dortmund in Germany.
Last year's bitter Champions League final defeat against Chelsea has also left its scars, with the Bavarians eager to rectify it by reaching their third final in four seasons.
"It is very good that we suffered this setback in our otherwise sunshine world," said midfielder Thomas Mueller. "This game raised a lot of questions in our safe, little world."
For the trip to Bayer Leverkusen, Bayern are expected to make two changes from Wednesday.
Bastian Schweinsteiger is available again after his continental suspension and will replace Luiz Gustavo in midfield.
Elsewhere, Mario Gomez could come back into the starting XI in the place of Mario Mandzukic, whose form has trailed off in recent weeks. Holger Badstuber remains sidelined, while Franck Ribery is lacking fitness.
Meanwhile, Leverkusen will be sweating over the fitness of Omer Toprak, who was forced out of the game against Stuttgart with a knee injury two weeks ago, and missed the trip to Mainz.
The only absence is Karim Bellarabi, who is unfit, while Sebastian Boenisch may slot back in on the left-hand side of defense instead of Michal Kadlec.
Bayer sit comfortably in third place in the Bundesliga table heading into the match – and will remain there after the weekend’s fixtures, with Schalke and Eintracht Frankfurt six points behind – but fell to a 1-0 defeat against Mainz last time out.
Though Bayern were able to break even more records with a 3-2 Bundesliga win at home to Fortuna Dusseldorf, the nature of their late win against the top flight new boys after twice trailing showed brief glimmers of what came midweek against another side able to go all for broke.
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Sunday March 17