Jürgen Klopp and Neven Subotic returned to haunt their former stomping ground and, though Marco Caligiuri opened the scoring for Mainz with a vicious volley early on, it turned into the Robert Lewandowski show as the Polish international bagged a brace to clinch all three points for the titleholders.
Fast and furious
The frantic pace of the early exchanges came as no surprise, but an opening goal inside five minutes certainly caught a few people off-guard - including Dortmund. Elkin Soto acted as the creator to flick the ball into the path of Caligiuri, who needed just one touch to leather a left-footed volley past Roman Weidenfeller and into the top corner from 20-yards.
The visitors soon began setting their stall, however, and managed to level the scores shortly before the quarter-hour mark. Marcel Schmelzer battled for possession by the corner flag before setting up Marco Reus to deliver a dangerous cross that only needed the slightest of touches from Lewandowski to find the back of the net.
The early equaliser took the wind out of Mainz's sails and allowed Dortmund to wrestle control away from them, yet with both sides pushing forward at break-neck speed, it was the hosts who continued to carve out the better opportunities. Nicolai Müller dragged his effort just wide of the far post having caught Mats Hummels in possession, before Andreas Ivanschitz followed suit with a similar attempt after tying Borussia's backline in knots on the counter.
However, in not converting their chances Mainz opened the door for Dortmund to take the lead, an opportunity the champions made the most of on the stroke of half-time. Lewandowski peeled off his marker to collect Moritz Leitner's pass and demonstarted the presence of mind to lift the ball over the onrushing Christian Wetklo, handing Dortmund a narrow lead at the break.
Toning it down
Mainz came out in the second half with hopes of playing their way back into contention, but had Wetklo to thank for rushing off his line to deny Lewandowski his hat-trick soon after the restart. The visitors were making their presence felt against their opponents' technically-savvy individuals, limiting Dortmund in the midfield battle, whilst preventing them from breaking forward quickly.
With neither side giving their opponents an inch, Dortmund seemed content to take the sting out of the encounter. Reus cut out Marcel Risse's drilled cross with the relatively anonymous Adam Szalai lurking at the back post, while at the other end Subotic failed to make proper contact on a half-chance inside the box.
Lewandowski was on the hunt for his third goal, but having powered his way past two Mainz defenders, could only ruffle the side netting with an improvised toe-poke. The hosts didn't give up hope, but struggled to find away past Borussia's organised defence as the champions hung on for all three points.
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