Reigning champions Borussia Dortmund go into their showdown against Borussia Moenchengladbach on Saturday admitting their defensive weaknesses are proving to be fatal.
Dortmund twice gave up leads in their 3-3 draw against high-flying Eintracht Frankfurt on Tuesday following a 3-2 defeat at Hamburg last weekend that brought their 31-match unbeaten run to an end.
It is their defensive frailties that are currently causing most concern to the two-time reigning champions.
"It's fatal that we're allowing so many goals in. We are just not working as well at the back as we did last year," said Dortmund captain Sebastian Kehl.
Dortmund have already conceded eight goals in their opening five games, compared to 25 in the whole of of last season and 22 in 2010-11.
Coach Jurgen Klopp called for calm though, saying: "We have to keep our composure and address the correct areas. Some fine-tuning needs to be done but there is no need for massive changes."
Dortmund sit sixth in the table and are already seven points behind leaders Bayern Munich.
"I don't care about the gap. We can do more and are not where we belong," added Kehl.
Dortmund actually find themselves in almost the same situation as 12 months ago, when they trailed Bayern by eight points after seven games before eventually winning the title.
Saturday's home clash with Gladbach will be a special occasion for Dortmund forward Marco Reus, who moved to the champions in the summer after scoring 36 goals in 97 Bundesliga appearances in three years with the Foals.
Reus missed the Frankfurt game with an ankle injury but should be available to face Gladbach.
Bayern travel to Werder Bremen earlier on Saturday having won all of their first five matches, but the Bavarians are refusing to get carried away.
"We have only played five of 34 matches. We have to keep both feet on the ground," said Dutch winger Arjen Robben.
"We are playing good football. But there's no reason to break out in euphoria," added chairman Karl-Heinz Rummenigge.
Bremen picked up an important victory away at Freiburg on Wednesday, but the northern outfit have not beaten Bayern in seven attempts, and not at their own Weserstadion since October 2006.
Promoted Eintracht Frankfurt gave up their first points of the season despite another impressive display against Dortmund and Armin Veh's team are expected to get back to winning ways when they host Freiburg on Sunday.
"It was great how the team fought back, and we did it against Dortmund, too, not just against anybody," said Veh, whose team's playing style has earned widespread plaudits so far.
Meanwhile, third-placed Hannover travel to Hamburg on Saturday with their Hungarian international midfielder Szabolcs Huszti, who has three goals and seven assists in his last three games, the man to look out for.
Bayer Leverkusen host Greuther Fuerth, while Stuttgart coach Bruno Labbadia's job is under threat ahead of his side's trip to Nuremberg.
Friday's match, Fortuna Duesseldorf vs Schalke 04, ended in a 2-2 draw.
Fixtures:
Saturday
Bayer Leverkusen v Greuther Fuerth, Werder Bremen v Bayern Munich, Nuremberg v VfB Stuttgart, Hoffenheim v Augsburg, Hamburg v Hannover 96 (all 1330), Borussia Dortmund v Borussia Moenchengladbach (1630)
Sunday
Eintracht Frankfurt v Freiburg (1330), Wolfsburg v Mainz 05 (1530)
