The 44-year-old trainer felt mistakes were key to seeing his side drop two points, which could allow Bayern Munich to close the gap at the Bundesliga summitBorussia Dortmund coach Jurgen Klopp was disappointed with the manner in which his side were held to a 4-4 draw by Stuttgart.
The Bundesliga champions could not hold on to a late lead as an injury-time goal from Christian Gentner restored parity again.
Dortmund had also wasted a two-goal early on, when three quickfire goals from Stuttgart saw the visitors turn the score around, and Klopp was irritated with his side's schoolboy errors.
"There were one or two situations that we have never seen before," Klopp told reporters after the game.
"How Neven Subotic and Mats Hummels both went for the header [in Stuttgart's fourth goal], I cannot even respond, because something like that has never happened before."
Meanwhile, Hummels praised Dortmund's fighting spirit but lamented that the team suffered a goal in the dying stages of the match.
"We must never give away a 2-0 lead," he said. "But we played incredibly well after we were down 3-2.
"We went at a pace that our opponents could not contain. But then we allowed such a dirty equaliser."
Bayern Munich will have the chance to close the gap on Dortmund to three points in Saturday's trip to Nurnberg.