Willy maybe I'm misunderstanding you too but Rangers can still close the gap without Celtic losing any games. Rangers just have to drop fewer points against the other teams than they did last season.
Unless by 'close the gap' you mean 'close it to zero'?
ETA: Doh! I've just realised that we've all been playing fast and loose with the English language and Willy's half right. If Celtic maintain last season's record, Rangers can't close the gap, they can only narrow it.
However... Celtic could remain 'invincible' next season but still only get 38 points, in which case Rangers can close the gap.