Borussia Dortmund coach Jurgen Klopp has admitted that Schalke deserved to defeat them in the Revierderby on Saturday.
Goals from Ibrahim Afellay and Marco Hoger saw the Royal Blues win 2-1 at the Signal-Iduna Park in the Bundesliga.
"We did not play well until we made a change to our system after half an hour," said Klopp.
"We were a little more stable from there onwards. We played enough football, but overall it was a deserved win for Schalke."
Dortmund are now 12 points behind league leaders Bayern Munich.