Dutch midfielder Nigel de Jong is doubtful for the Netherlands' World Cup quarter-final after injuring a groin in the victory over Mexico on Sunday, coach Louis van Gaal said.

Van Gaal said the injury was a "big setback" as he plans for the Salvador quarter-final on Saturday. The AC Milan player came off the field after just nine minutes.

De Jong's return "will be difficult for the next match," van Gaal told reporters after the 2-1 win took his side through to the last eight.