The matches against Mainz are always difficult. Leverkusen have a match against Mainz and I don't know who will win. We are talking about a team that has given Bayern a hard time. It will be a difficult match for Leverkusen. It will be very important to win this match but Leverkusen will have to beat Dortmund first. The Dortmund match is more important for them.
Fact. Because these two games will not be very easy for Bayer Leverkusen, because both Mainz and Dortmund always value their home game, and if you consider the game of Dortmund is a home game for them, which means they will not take it a bit easy in Bayer Leverkusen, because if care is not taken, they might lose the game against Dortmund. From the look of things, it is either they lose that game or go on a draw with Dortmund. I know that I am not too sure they will be able to win against Dortmund in the game.
Talking of their game with Mainz, they might have a bit of a chance of winning if they maintain their defence more than expected because we see how Mainz played against Bayern Munich, which I think they will put the same effort or even more into their performance when they are playing against Bayer Leverkusen.