Celtic beat Rangers in a penalty shootout following a goalless Scottish Cup quarter-final at Ibrox Stadium as a massive pitch invasion sparked violent clashes.Tomas Cvancara scored the winning penalty for the visiting side before hundreds of rival supporters stormed the field to exchange missiles and flares.Police Scotland and the Scottish Football Association have launched immediate investigations after several arrests were made and a technical staff member was attacked.The disturbance marks a significant setback for plans to increase away fan attendance at the historic
Old Firm derby following years of seating restrictions.