Borussia Dortmund and Mainz exchanged blows but neither was able to land the knockout as they shared a 0-0 draw at the Westfalen Stadion.
Andre Schurrle had Mainz's best chance midway through the second half before Lucas Barrios scuppered a similar opportunity for Dortmund late on in a very even match with few chances at either end and just one yellow card.
Dortmund coach Jurgen Klopp had to accept a point against his former side, who moved above defending champions Wolfsburg with the point.
It was the first time Klopp came up against his former club since leaving them 18 months ago after 18 years at the club.
He had promised to celebrate any goal his current side scored, even though he remains a Mainz fan, but he was not even given the opportunity.
His side started well, though, with Barrios setting up Mats Hummels for the first chance of the game in the fifth minute, but he wasted the opportunity.
Nelson Valdez then headed a Markus Feulner free-kick onto the roof of the net as Dortmund made the better start to the game.
However, Mainz looked comfortable in defence and, as the game progressed, they started to grow in confidence themselves with Aristide Bance shooting over at the end of a good counter-attack on the half-hour mark.
Hummels almost gave Dortmund the lead five minutes before the break, but Heinz Muller made a good save from his volley.
Mainz's best chance fell to Schurrle, who lifted the ball over Roman Weidenfeller, but he was denied a goal by the covering Marcel Schmelzer.
Barrios then wasted Dortmund's best chance of the game when he failed to beat Muller in a one-on-one situation at the other end.
