celtic were knocked out of the scottish cup semi-final by inverness after officials failed to award them a penalty for a blatant handball .
their cup exit ended any hopes of securing a domestic treble this season .
rangers legend john brown experienced similar frustration in 1989 , when the ibrox side also missed out on winning three trophies due to poor officiating .
but brown says that celtic 's complaints about the incident are ` sour grapes '