Bayer Leverkusen return from the Bundesliga's winter break with victory at Borussia Dortmund to maintain the pressure on leaders Bayern Munich.

A second-half goal from Alex Grimaldo sent Bayer Leverkusen to a 1-0 home win over Mainz, closing the gap with league leaders Bayern Munich to one point. With half the season played, Dortmund sit ninth,

The two standout German teams from last season are on opposite trajectories as the pressure mounts in the Bundesliga and Champions League.

Borussia Dortmund and Bayer Leverkusen have seen players who have played for both clubs. This has somewhat become a norm.