Celtic's dreams of a domestic treble remain on course as they progressed to the Scottish Cup quarter-finals with a 1-nil win over nine-man Rangers, who also had El-Hadji Diouf ordered off after the final whistle, amid shameful scenes at Parkhead.
An uneventful match turned ugly just after the half-hour mark when two yellow cards in eight minutes saw Steven Whittaker sent off sparking trouble on the sidelines with El-Hadji Diouf involved in a confrontation with Celtic manager Neil Lennon.
The Hoops made their numerical advantage count in the 48th minute when Mark Wilson scored at the second attempt as Sasa Papac, who had blocked his initial shot, lay dazed on the line.
Madjid Bougherra received his marching orders three minutes into stoppage time after picking up his second yellow while Diouf was shown a straight red for his protestations at the whistle, in a match where nine players were booked.
More trouble erupted when Lennon and Rangers assistant manager Ally McCoist had to be separated.