Midfielder Ryan Carr insists St Mirren will do everything in their power to retain their League Cup trophy as they travel to Rangers in Sunday's last 16 tie. The Buddies, led by Stephen Robinson, beat Wilfried Nancy's Celtic 3-1 at Hampden last December to lift the domestic cup for the first time in 12 years. Craig McLeish's side emerged from the group stage to set up a knock out tie against Rangers and Carr insists the Buddies are up to the challenge.