Coach Thomas Tuchel was thrilled with how Borussia Dortmund reacted following their demoralising defeat to Bayern Munich prior to the international break.
Dortmund defeated Mainz 2-0 in the Bundesliga on Friday thanks to goals from Marco Reus and Henrikh Mkhitaryan.
The away win came at the perfect time for Dortmund, who were humbled 5-1 by league leaders Bayern on October 4.
Tuchel - coming up against his former club for the first time - was pleased with how his side responded.
"That was a tough game against strong Mainz," he said. "They were compact and hard-working. There were many phases in which we suffered today on the pitch, because we had to chase.
"It's been noted that the three draws, including in the Europa League, and the violent 1-5 in Munich, have dented confidence in our play. But there were also periods where we have done well and earned good opportunities.
"We had to diligently defend and force Mainz errors. I know how hard it is to win here.
"We know the importance of these three points and I am sure that we return a lot of confidence."
Reus missed a penalty just after half-time, but Tuchel was thankful it did not mean anything in the end.
"I was very happy for him, and also the fact that this goal would have been enough to win so the missed penalty decreases in its importance," he said.
"Marco has unlocked the door today and paved the way for us to win."
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