Kai Havertz and Bukayo Saka struck in the first half to hand Arsenal an impressive 2-0 Champions League win against Paris St Germain at the Emirates.Havertz opened the scoring after 20 minutes before stand-in captain Saka doubled his side’s advantage with 10 minutes of the first half remaining.The French champions hit the post and crossbar, but Arsenal saw out the match to secure a statement win.