Luke McCowan made his Celtic debut off the bench yesterday and played a part in the Bhoys’ comprehensive 3-0 victory over Rangers. The 26-year-old completed a deadline day move from Dundee for £1 million to shore up Brendan Rodgers’ midfield ahead of the cut-off point. Despite several bids from Hibernian, McCowan only wanted Celtic and was named as a substitute at lunchtime on Sunday. Eventually getting his chance, Rodgers praised the new signing for his contribution and believes he will be an ‘important’ figure over the course of the season. He stated: “It’s so nice for him. I think it was a …