Harry Kane scored his fourth Bundesliga treble in an all-round masterclass to help Bayern Munich crush second-bottom Mainz 8-1 at home on Saturday and trim Bayer Leverkusen’s lead to seven points. Leon Goretzka was on target inbetween the England striker’s first-half double, thanks to Kane’s clever leave, and after a thumping free-kick from Nadiem Amiri failed to derail the improving champions, Thomas Müller, Jamal Musiala and Serge Gnabry netted. Kane then headed in his 30th goal of his maiden Bundesliga season as he eyes Robert Lewandowski’s league record of 41 goals in a campaign before Gor…