The Werkself were two goals ahead in the 83rd minute before an own goal and a late equaliser restored parity.
“It pisses me off,” Adler said after the game, according to Kicker. “We were 2-0 up and still failed to win due to lapses of concentration.
“You would think that some of us do not even want to play in the Champions League. We play in the Bundesliga and not the Bezirksliga [District League], everyone should know this.”
Skipper Simon Rolfes echoed his goalkeeper’s sentiments: “We long had victory in our hands. I cannot explain why we were so passive in the final minutes.”
Leverkusen, who are desperate to hold onto second place and secure automatic Champions League qualification, missed out on a clear chance to go six points ahead of Bayern Munich on Sunday. Instead, die Werkself are four points clear of their Bavarian rivals, and 12 points behind leaders Dortmund.