Dortmund beat 10-man Cologne to tighten grip on top-four spot

Goals from Serhou Guirassy and Maximilian Beier took Borussia Dortmund to a 2-1 win at Cologne on Saturday, tightening their grip on Champions League qualification.Hoffenheim took a step towards a second Champions League qualification with a 4-2 win at last-placed Heidenheim to stay in third.