Paul Hartley believes Celtic midfielder Aiden McGeady has the class to unlock Shakhtar Donetsk's defence this week.
Manager Gordon Strachan, who expects Shakhtar to come and attack, believes that the credit for the sheer incline in the graph of McGeady's progress belongs to the player himself.
"You become more confident the better you become physically," he said. "When you don't get tired you don't make mistakes and when you take them away your confidence flows. Sometimes Aiden used to try too hard and then get down on himself when something miraculous didn't happen. I think his game has also got simpler but better. Plus he has incredible pace."