Bayern Munich were unable to retain their 10-point lead at the Bundesliga summit after being held to a 0-0 draw by Bayer Leverkusen, who played for more than half an hour with 10 men.
Carlo Ancelotti made five changes from the 2-1 Champions League defeat to Real Madrid on Wednesday to keep key players fresh for Tuesday's return leg, but those who came in failed to impress and RB Leipzig now sit just eight points back after a 4-0 thumping of Freiburg earlier in the day.
Douglas Costa and Kingsley Coman were unable to make a meaningful impact in place of first-choice wingers Franck Ribery and Arjen Robben, while Thomas Muller again lacked sharpness in front of goal in the absence of suspended top scorer Robert Lewandowski.
READ MORE: How Bayer v Bayern Munich unfolded
Bayern laboured early on and it was not until after the half-hour mark that they looked like breaking through, David Alaba and Arturo Vidal denied by two goal-line clearances in quick succession from Leverkusen.
Coman also failed to convert from little more than six yards out, but the balance appeared to tilt in Bayern's favour when Tin Jedvaj was shown a second yellow card for a reckless challenge on Muller in the 59th minute.
Ancelotti sent Robben, Xabi Alonso and Philipp Lahm on - the Dutchman making his 250th competitive appearance for the club - in a bid to improve his side's creative prowess, but a goal that would have put them two wins from the title never came and they will need to pick themselves up ahead of the trip to the Santiago Bernabeu.
A poor touch from Kevin Volland denied the forward the chance to test Manuel Neuer in the ninth minute, while Julian Brandt – the subject of ongoing reported interest from Bayern – lost his footing and fired over when found by Volland 12 yards out.
Bayern enjoyed the majority of possession but it was not until the 32nd minute that they really threatened Bernd Leno's goal.
Alaba saw his shot blocked by Jedvaj before being cleared off the line by Wendell, with calls for handball to be given against the Croatian ignored by referee Daniel Siebert.
Leverkusen were unable to remove the danger, though, and Vidal came close seconds later. The Chilean looped the ball over Leno before heading it goalwards, only for Omer Toprak to keep it out with a last-ditch slide.
Bayern were unrelenting but Coman was unable to break the deadlock before half-time as he fired straight at Leno from just outside the six-yard box after Muller picked him out at the back post.
Early in the second half Muller hesitated after being set free on the right-hand side of the box, but managed to work the ball over to Vidal whose shot was blocked.
Bayern were given a boost before the hour mark when Jedvaj was dismissed having hauled down Muller as the Germany international chased a long ball, and Ancelotti responded by sending Robben on for Costa.
Lahm swept Muller's cross narrowly wide from inside the six-yard box in the 84th minute and Robben sent a back-post header into the side-netting in stoppage time as Bayer Leverkusen held firm.
Tayfun Korkut's side now sit 11th, just four points adrift of what could be a Europa League qualification spot, although the distance to the bottom three is the same.