Mainz become slightly more courageous in the second half but were mercilessly punished by BVB, who effectively used of the space afforded to them. They had 11 shots in the first period – more than in any other away match this season. Here are the match facts.
Strong record: Borussia Dortmund have picked up 105 points in 49 Bundesliga matches since Lucien Favre's arrival. No other team has amassed more points during that time (Bayern also have 105 points since then).
Quiet day at the office: Roman Bürki was the hero against Slavia Prague but a focused defensive performance from BVB meant he did not have a single save to make today.
Landmark figures: Marco Reus scored his 125th Bundesliga goal – 50 of which have been the first of the game.
Long-range effort: Marco Reus' opener was Dortmund's first goal from long-range (outside the box) in the Bundesliga this season.
Goal machine: Jadon Sancho scored for the sixth match in a row and, like Reus, set up a goal too. Sancho was heavily involved in the game (81 touches) and won 65 percent of his challenges.
Record run: Thorgan Hazard has now netted in three consecutive Bundesliga games – his longest such scoring run.