The Dutchman is glad to be back at the Imtech Arena, and speaks of the boost in morale at the club ignited by their recent 3-2 success over the Bundesliga champions
The Rothosen started their campaign with three defeats in a row, but racked up their first points of the season against the title holders, and the summer arrival from Tottenham hopes the result can kick-start a period of sustained form.
"The beautiful feeling is still there. We must now take this into the next game," the Netherlands midfielder told Bild.
"Dortmund were the dominant team, but no-one believed in us. Now we have earned respect. Suddenly, we think we can beat anyone."
But while he savoured the winning feeling, the 29-year-old warned his team-mates against complacency ahead of their forthcoming meeting with Borussia Monchengladbach on Wednesday.
"We have to stay on the ground and be focused from the start, as we were against BVB. Now we can show how good we really are," he explained.