Bayer Leverkusen and Bayern Munich shared a goalless stalemate for the first time since 1990 as the record German champions failed to take full advantage of Borussia Dortmund's draw in Berlin.
After second-placed Dortmund had been held by Hertha earlier on Saturday, Bayern restored their eight-point advantage at the top of the table in the late kick-off, but will have felt they could have extended it to 10 - particularly following the introduction of Thomas Muller in the second half.
In the end, Bayern had to settle for just a point in a match they finished with 10 men, Xabi Alonso receiving his marching orders five minutes from time.
Bayern coach Pep Guardiola, who will take over at Manchester City at the end of the season, had warned about the potential aerial threat of Stefan Kiessling, but it was Omer Toprak who met a Hakan Calhanoglu corner to give Manuel Neuer work to do in the 11th minute.
Bayern slowly started to take control of proceedings after that, however, and it was they who posed the greater threat in a largely tactical first 45 minutes.
Arturo Vidal's return to the BayArena to face his former club ended early in the second half when he took a Karim Bellarabi shot on his head and struggled to regain his bearings, with Thiago Alcantara replacing him.
An otherwise quiet Javier Hernandez decided to use one of his rare touches of the ball to have a shot from long range, only just missing the far post and sparking a good spell for the hosts, with chances finally starting to arrive.
Substitute Muller wasted Bayern's best chance of the game just past the hour-mark when he volleyed Kingsley Coman's cross over from close range, before he spurned another opportunity from Douglas Costa's pull-back soon after.
Muller's introduction certainly gave Bayern a lift, but it also inspired defender Toprak, who was desperate not to let Bayern through.
He denied Muller repeatedly before his central defensive colleague Jonathan Tah made a mistake which should have been punished by Robert Lewandowski, only for the Pole to fire wide.
Alonso was dismissed for a second yellow card moments later, giving Leverkusen some respite for the final five minutes, but they were unable to take full advantage.
Julian Brandt flashed a shot wide of Neuer's far post, but it was Lewandowski who could have snatched victory in stoppage time with the final chance of the game only to see the opportunity go begging.
It was only the third time Bayern had failed to win in the league this season but the draw nevertheless enabled them to remain eight points clear at the top of the Bundesliga, while Leverkusen dropped back out of the Champions League qualifying berths to fifth, due to Schalke's win over Wolfsburg.
A game tipped as the battle of the two most in-form attacks in the Bundesliga ended up being decided by two of the best defences in the division.