A German referee has apologised after awarding Bayern Munich a penalty that should not have been given in yesterday's DFB-Pokal semi-final against Werder Bremen.

Arturo Vidal appeared to dive and win the penalty, which Thomas Muller converted to seal a 2-0 win, and the Chilean has been criticised for the way he threw himself to the ground.

Referee Tobias Stieler told Kicker: "It happened so quickly and I was in a good position. I saw a contact, but there wasn't any. I'm sorry."

Bayern boss Pep Guardiola, chief executive Karl-Heinz Rummenigge and Muller have all admitted that it was the wrong decision.