Borussia Dortmund sit just three points ahead of Bayern Munich at the Bundesliga summit after a disappointing 0-0 draw against bottom club Nurnberg on Monday.
Bayern's 3-2 win over Augsburg on Friday cranked up the pressure on Lucien Favre's side and they were unable to respond, labouring to just a solitary point against a team that has won only twice in the league this season.
Dortmund came up against a goalkeeper in inspired form, Christian Mathenia producing a string of fine saves to frustrate the visiting team's attackers, most notably Mario Gotze.
The result means that Dortmund have now gone five games in all competitions without a win, while Nurnberg are now five points away from safety.
Any thoughts that Dortmund would sweep aside their lowly opponents were dispelled in the early stages with Nurnberg looking significantly more robust than they did during September's 7-0 thumping at Signal Iduna Park.
Their positive start was almost rewarded before the half-hour mark, Hanno Behrens twice going close with headers. His first effort was pawed over by Roman Burki and the unmarked Nurnberg captain powered over from eight yards from the resulting corner.
An out-of-sorts Dortmund belatedly woke from their slumber in the closing stages of the first half, carving out a number of clear opportunities to take the lead.
Gotze was twice denied by excellent stops from Mathenia, while Axel Witsel saw a close-range effort deflected into the side netting.
Mathenia got down sharply to again deny Gotze shortly after the break, while the Germany international flashed wide from a promising position soon after.
Substitute Jacob Bruun Larsen had a late strike rightly ruled out for offside, but all three points would have flattered Favre's stuttering side, who could be level on points with Bayern by the time they host Bayer Leverkusen on Sunday.