Speculation has suggested that Philipp Wollscheid could see a loan deal at Mainz cut short but he is ignoring move talk.
Bayern Munich won to move seven points clear in the Bundesliga as a Werder Bremen win sent Borussia Dortmund bottom.
Bayer Leverkusen were frustrated in their search for three points as they were held to a goalless draw by Mainz.
A second-half double from Son Heung-min earned Bayer Leverkusen an impressive 2-1 win at Zenit St Petersburg on Tuesday.
Bayern Munich took the honours in the big clash in the Bundesliga, coming from behind to beat Borussia Dortmund 2-1.
Hamburg stunned high-flying Bayer Leverkusen to pick up a rare win and move out of the Bundesliga bottom three.
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