BVB conceded after just nine seconds in their opening game of the new Bundesliga season and the 47-year-old coach has shouldered the responsibility for his side's sluggish start
Last season's Bundesliga runners-up had hoped to hit the ground running on the opening day of the 2014-15 campaign but they fell behind right from the kick-off, with Karim Bellarabi claiming the record for the fastest goal in the history of the German top flight by netting after just nine seconds of action.
The winger then set up Stefan Kiessling for a second Leverkusen goal in the dying seconds, thus leaving Klopp ruing his side's sluggishness in the early exchanges at Signal Iduna Park.
"The start to the game hurt, of course," the BVB boss told reporters. "Leverkusen used their plan; we, unfortunately, did not.
"We have a lot of work to do. That we were not awake at the beginning I blame on myself.
"Our feeling in the first 25 minutes was influenced dramatically after the early goal.
"The team has shown great will and if we'd taken one of our chances, then we would have turned the game. But Bayer earned their win."
Although he alluded to his attack's profligacy in front of goal, Klopp insisted that he did not want to single anyone out for criticism.
"[The finishing] was obviously bad, but the [forwards] have not screwed up alone," he pointed out.