Bayern Munich have said referee Alberto Undiano Mallenco's officiating in Tuesday's 0-0 draw against Shakhtar Donetsk was not worthy of the Champions League.
Shakhtar and Bayern drew 0-0 in Ukraine, with Bayern reduced to 10 men after Xabi Alonso -- making his 100th Champions League appearance -- was sent off by the Spanish official for two yellow cards.
Mallenco also booked Bayern's Rafinha, Jerome Boateng and Bastian Schweinsteiger, while Shakhtar's Dario Srna, Fred and Douglas Costa, who appeared to elbow Franck Ribery just minutes before Alonso's red, were shown yellow cards.
"It was a very strange performance by the referee," Bayern sporting director Matthias Sammer told Sky Deutschland.
Sammer refused to go into detail or comment on Douglas Costa's yellow card, adding: "The player is not standing next to me and can't defend himself."
Bayern coach Pep Guardiola refused to comment on his compatriot Mallenco, but said his team "being reduced to 10 men for a long, long time" was one of the reasons for the goalless draw.
However, CEO Karl-Heinz Rummenigge told Die Welt: "I have to clearly say that the referee was a catastrophe. What this man showed here was far from Champions League standard."
Rummenigge said Alonso's second booking "was no yellow -- the decision was not OK from my point of view."
"Fundamentally, I think it was a debatable performance by the referee," he added. "Donetsk played extremely rough, and when the referee lets the players get away with it there will usually be no flow of play."