The Gulf emirate and its football administrators are hoping to silence sceptics who have pointed to a lack of football pedigree after being controversially chosen to host the 2022 tournament.
But local people need to start filling stadiums that in most cases have been no more than three-quarters full at the ongoing Asian Cup, Ghotbi said.
"The world is watching Qatar to see if they are capable of hosting the World Cup," he said ahead of the clash Tuesday with rivals Iraq.
"I think it's important the seats in the stadiums are full and I encourage people to come to the stadiums and cheer for football, not just Qatar."
Qatar, which is smaller than the Pacific island of Vanuatu or the American state of Connecticut, won the right to host the World Cup ahead of Australia, Japan, South Korea and the United States.
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