In their last friendly game before the start of the season Leverkusen have lost to Chelsea 2-0. The game was a total dominance by Chelsea with ball possession of 70% and 24 shots on goal (9 on target) Vs. Leverkusen's only 4 shots (2 on target).
Judging by this game alone, things are not looking very bright for Ten Haag's team.
They further strengthened their squad in the recent days by completing acquisition of goalkeeper Janis Blaswich (Leipzig) and right winger Ernest Poku (AZ Alkmaar). We'll see if that will make any difference.
Tomorrow they are playing against SG Sonnenhof Großaspach (a Regional League club) in the first round of the DFB Pokal. Anything other than a convincing win by Bayer will be a red flag.