Borussia Dortmund struggled to a 2-1 win over fourth-division side Koblenz in a friendly last night, but the result was the least of coach Jurgen Klopp's concerns as he faces up to losing another player to injury.

Julian Schieber scored the second goal three minutes from time as the defending German champions came from behind to win, but two minutes later, Kevin Grosskreutz was forced to leave the field. The Germany international took a knock to his right foot and will undergo tests later today.

Dortmund lost Jakub Blaszczykowski for six weeks, Sven Bender for a fortnight and Mats Hummels for up to two weeks after the trio were injured against Hannover at the weekend.

Elsewhere, Hamburg used the break for international matches to defeat local side VfL Hamburg 6-0 and Mainz won 4-1 against Pfeddersheim with a side largely made up of reserve players.