Thomas Tuchel believes the 5-1 thrashing Borussia Dortmund suffered at the hands of Bayern Munich in October helped mould his team into Bundesliga title challengers.
Bayern were rampant in that match at Allianz Arena, dispatching their closest rivals with ease.
Since then, Dortmund have enjoyed an impressive run of form and Pep Guardiola's champions will arrive for the next 'Klassiker' clash at Signal Iduna Park on Saturday just five points clear at the top.
Tuchel said: "The reverse fixture showed that you can lose by a high margin because of small errors. But you can learn from that.
"The 5-1 loss in Munich has made us into what we are now. And we are very happy with that.
"You could see our improvements in the games against Mainz and Augsburg following that loss in Munich."
Tuchel knows that while his side can close the gap this weekend, a defeat would effectively end their title hopes.
"We have the confidence to say that we're able to win.
"But we also can read the table. Bayern can turn it around decisively - which is why [we] expect them to be at their best.
"In order to beat Bayern we need a top performance. If we win, the situation will be different."
Tuchel reiterated his admiration for Bayern counterpart Pep Guardiola, who is hoping to land another Bundesliga crown before departing for Manchester City at the end of the season.
"I have already talked a lot about Pep, he has set new limits. He knows I value his work, he is probably the best [coach].
"We want to beat Bayern but there will be periods when we have to suffer. But if we're brave enough to play to our limit we can also make Bayern suffer."