Defending Bundesliga champions Borussia Dortmund lost a friendly match which was overshadowed by crowd disturbances at Club Bruges on Saturday.
Violent scenes just before the start of the game as groups of rival fans clashed meant a delay to the start with the Belgian Jupiler League runners-up eventually winning 3-1 with Leonardo Bittencourt on target for the Westphalians.
There were better fortunes for Borussia Monchengladbach, who defeated third-division Preussen Munster 3-0 with Igor de Camargo, Thorben Marx and Branimir Hrgota on target, while Hoffenheim beat Astoria Walldorf by the same scoreline.
Hamburg's slow start to pre-season continued as they were held to a 1-1 draw by Holstein Kiel with Maximilian Beister scoring for them.
Mainz defeated local rivals FSV Frankfurt 2-0 at the Bruchwegstadion with Eric Maxim Choupo-Moting and Anthony Ujah scoring for the Bundesliga side, while Greuther Furth thrashed TSV Hochstadt 18-0.
Finally, Nurnberg turned around a 2-0 deficit to beat fourth-division side SSV Ulm 3-2.