The Champions League group stage gets under way this week as Liverpool start the defence of the title they won with victory over Tottenham in Madrid.Here, PA takes a look at some of the main talking points before the first round of matches.Liverpool start title defence against familiar faces European champions Liverpool launch the defence of their title on Tuesday against a familiar foe in Napoli. Carlo Ancelotti’s side pushed the Reds all the way in Group C last season and went mightily close to denying them a place in the knockout rounds. The Italians, runners-up to Juventus in Serie A in three of the last four seasons, beat Jurgen Klopp’s side 1-0 at the San Paolo Stadium. Mo Salah’s solitary goal in the return at Anfield, coupled with a clean sheet, ensured the Merseysiders progressed at their expense – but only after Alisson’s brilliant stoppage-time save had denied Arkadiusz Milik.Tottenham out to go one better than last season’s finalTottenham kick-started their season in time for their return to Champions League action with a convincing win against Crystal Palace at the weekend. Spurs had struggled to get going since their memorable run all the way to the final in May, but…