Grasshoppers saw a second Swiss Super League match called off in the space of six weeks after fans reportedly told players to hand over their shirts, shorts and socks in Sunday's game with Luzern.
Switzerland's most successful club were trailing 4-0 at Swissporarena, a result that was set to seal their relegation to the second tier for the first time in 70 years.
The match was halted in the second half when a large number of visiting fans moved to the front of the stand, causing riot police and stewards to form a line blocking their access to the pitch.