After 15 matches of the Premier League season, the leaders have a two-point lead. Last season at this stage, Manchester City had an eight-point cushion. In 2016/17, the gap at the top was three points. In fact, the last time the Premier League leaders had a smaller points gap to second at this stage of the season was in December 2008. By those standards, we have the makings of a titanic title tussle.