A friendly match between Benfica and Fortuna Duesseldorf was abandoned in the 39th minute on Saturday when the referee was knocked to the ground shortly after sending off a player.
Television footage showed Benfica captain Luisao protesting referee Christian Fischer's decision to eject teammate Javi Garcia. Brazilian international Luisao then appeared to shove Fischer.
Luisao approached the referee in a menacing manner and sent him falling backwards, where he lay for several seconds apparently unconscious before coming back to his senses after players and linesmen called for a doctor.
Fischer got back to his feet and decided to abandon the game.
Fortuna returned to play a further 45 minutes without their Portuguese opponents, splitting their squad into two sides of 11 men to ensure the fans at the Dusseldorf Arena were given some value for their money.
Duesseldorf said in a statement on its Web site that Fischer received treatment from its team doctor but decided against resuming the match.
Newly promoted Duesseldorf will play in the Bundesliga this season.
Information from The Associated Press was used in this report.
