Dundee United have apologised to Ross County after more than 70 seats were broken in the away end at the Global Energy Stadium.
Seven fans were arrested on Saturday as graffiti and stickers were also splashed on the County stand.
"After an excellent Scottish Cup quarter-final victory and tremendous backing from the vast majority of the 1,413 Dundee United fans who made the trip to Dingwall, it is extremely disappointing that such an apology has had to be made." said United.
"Having received clear evidence of damage to seats in the North Stand, which housed the United fans, as well as reports of seven arrests within the stadium, the club will continue to do everything in its power to prevent this type of behaviour, which is detrimental to the proud reputation of Dundee United and its fans.
"Make no mistake, Dundee United are fiercely proud of our extremely loyal and passionate support who, over a difficult season, have given unequivocal backing to the team.
"Most of our fans on Saturday behaved in entirely the proper manner, showed superb support and played a large part in helping secure victory.
"We simply cannot allow the inappropriate behaviour of a few individuals to stain that reputation."