Germany midfielder Christoph Kramer has admitted he will probably never regain his memory of the time he spent on the field before coming off with concussion during the World Cup final.

"The doctors are certain that my memories of that part of the World Cup final will not come back," the Borussia Moenchengladbach player said in an interview with the weekly magazine Focus.

Kramer, 23, was in Germany's starting line-up against Argentina at the Maracana but lasted just 31 minutes before a violent collision with Ezequiel Garay left him concussed.

He had to come off and was left with no recollection of the first half hour.

The match referee, Italy's Nicola Rizzoli, told media after the final - which Germany won 1-0 - that Kramer had come to see him after the incident and asked him: "Referee, is this the final?"

The official immediately spoke to other German players about the strange enquiry and Kramer was immediately replaced by Andre Schuerrle.

He told Focus that doctors assured him there would be no after-effects.