What will of course trouble or perhaps instead puzzle most fans is just how Jurgen Klopp's side managed to succumb to such a performance with their best players on the park. Marco Reus was in attendance, peppering the opponent's goalmouth with chances, and so too was Ilkay Gundogan in midfield and Mats Hummels in defence. Yet there was one player missing from both games. A central midfielder who has returned to the squad and over the past two seasons quietly reestablished his presence on the side.
Nuri Sahin, Dortmund's playmaker, is what was missing against Cologne and Hamburg and is exactly who Klopp must ensure the club don't lose in the coming summer transfer window.