Bayer Leverkusen retained a two-point lead over Bayern Munich into their Bundesliga table topper next week, with Leverkusen winning 2-0 at bottom side Darmstadt and Bayern’s 3-1 over Borussia Mönchengladbach 3-1 marking Thomas Müller’s 500th career victory. Nathan Tella scored a 33rd and 52nd minute brace as Leverkusen regrouped well from a 0-0 draw against Gladbach eight days ago and remain unbeaten in all competitions. Gladbach led in Munich from Nico Elvedi in the 35th but the champions fought back from teenager Aleksandar Pavlovic in the 45th, league top scorer Harry Kane in the 70th and M…