Benfica's board of directors have urged their supporters not to attend away matches as a protest against several refereeing errors in Friday's 2-1 defeat at Vitoria Guimaraes.
"We want to ask the fans to continue supporting Benfica ... in the games at the Luz Stadium but to abstain from travelling to away games," the board said in a statement ahead of Tuesday's Champions League Group B opener at home to Hapoel Tel Aviv.
"Given the evidence of so many mistakes the hope of a serious (Portuguese) championship is still alive but it has been badly hurt."
Coach Jorge Jesus and football director Rui Costa criticised referee Olegario Benquerenca's decisions after Friday's match, including two Benfica penalty claims that were turned down.
After winning their first championship in five years last season Benfica have made a woeful start to their title defence, losing three of their first four games. They are down in 13th place, nine points behind leaders Porto.
The board also said the refereeing errors may persuade them to pull out of the League Cup this season.
No one at the Portuguese league's refereering commission was available for immediate comment.