Borussia Dortmund's Marco Reus and Raphael Guerreiro scored a goal apiece to beat visitors Union Berlin 2-0 on Wednesday and maintain their outside chances of securing a spot in next season's Champions League.

The hosts were awarded a controversial penalty after Reus went down in the box and although Erling Haaland's effort was saved, Reus stabbed home the rebound in the 27th minute.

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The Dortmund captain almost set up a second goal when he sent Giovanni Reyna through but the American's chip sailed wide.

Guerreiro did it better two minutes from the end, finishing a quick break to seal the three points for his team.

Union, whose keeper Andreas Luthe made a series of fine saves, twice hit the woodwork, including from a superbly-taken Max Kruse free kick in the 66th which diving Dortmund keeper Marwin Hitz palmed on to the post.

Dortmund moved to 52 points, four behind fourth-placed Eintracht Frankfurt, with the top four teams qualifying for next season's Champions League group stage.

VfL Wolfsburg, who face Dortmund on Saturday, tightened their hold on third place with a 3-1 win at VfB Stuttgart that lifted the Wolves to 57 points, one ahead of Eintracht and five clear of Dortmund.