If you’re going to make it as a Rangers number nine then it’s imperative that you do the business against Celtic on Old Firm derby day. As the scrutiny intensifies on Cyriel Dessers, the true test of the Nigerian international’s Ibrox credentials will come in clashes against the Gers’ eternal Glasgow rivals. But as Rangers reflect on the shortcomings of the club’s misfiring frontline, there is one long-term Ibrox-linked striker who’s just proved he has the mettle on derby day. It might also have a few at Rangers wondering if the club should’ve plunged given the 24-year-old’s pre-contract avail…