Bayer Leverkusen are the favourites while Hertha Berlin and Saarbrücken continue dreaming in a wide open German Cup campaign which reaches the quarter-final stage this week. The fact that two duels between second division teams kick off the action on Tuesday and Wednesday shows that anything appears possible this term. For only the second time in 60 years the top flight has just three teams left, VfB Stuttgart and Borussia Mönchengladbach along with the Bundesliga leaders Leverkusen. Gladbach face a tricky trip next week to third-division Saarbrücken who have already knocked out record winners…