Mario Goetze inspired Borussia Dortmund to a 2-0 win in Mainz, which means they overtake the oh-fives but they were also grateful to their goalkeeper Roman Weidenfeller, who made a vital penalty save.
Dortmund took the lead slightly against the run of play in the 27th minute. Niko Bungert's mistake allowed the lively Mario Goetze to dance a Halloween jig through the Mainz defence before drilling the ball home with authority past Christian Wetklo. The travelling Schwarzgelb support erupted, in contrast to Juergen Klopp who was more restrained than usual back at his old club.
The pivotal moment of the game was to come two minutes after the interval when Mainz were deservedly awarded a penalty. Neven Subotic was penalised for a clumsy two-footed lunge on Adam Szalai as the Hungarian looked to collect Sami Allagui's cutback. Eugen Polanski stepped up but was denied by Roman Weidenfeller who flung himself to his left to beat the ball away with both hands.
Dortmund then secured the three points and top spot at the midway point of the second period. Goetze turned provider, playing a beautifully weighted through-ball to Lucas Barrios, who just about stayed onside before coolly rounding Wetklo and blasting home into the vacant goal, more than compensating for his earlier glaring miss.
Mainz had begun the better and more confident of the two sides as they put pressure on a fragile looking Dortmund side, who showed the same hesitancy they displayed against Hoffenheim. However, Thomas Tuchel's side could not trouble the scorers despite half-chances for Sami Allagui and Adam Szalai.
The first golden opportunity of the game fell to the prolific Lucas Barrios on 14 minutes as he exploited a shambolic offside trap to race clear but he could only roll the ball past Wetklo but also inches past the post. Dortmund created a host of opportunities before the interval through Goetze and Barrios but had to content themselves with a one-goal lead at the break.
Mainz stepped it up in the second half, showing even more passion and a willingness to chase down every lost cause. Not even the penalty save took the wind out of their sails, as Roman Weidenfeller was called upon to make excellent stops from both Sami Allagui and Christian Fuchs either side of the second BVB goal, which did kill off Thomas Tuchel's young side.
Mainz's second defeat of the season (the other also came at home) means they drop down to second spot with 24 points, still six clear of third placed Leverkusen. They travel to Freiburg next weekend. Table-toppers Dortmund travel north to face overachievers Hannover 96.