Ecuador have filed a formal complaint with World Cup organisers after approximately 1,000 Mexico supporters gathered outside the Ecuadorian squad's hotel in Mexico City on Monday night, creating a deliberate disturbance ahead of their last-32 fixture.

The fans staged what local media described as a noisy serenade, banging pots, pans, and noisemakers while singing the Mexican folk song Cielito Lindo. Police eventually dispersed the crowd, but not before Ecuador's football federation had seen enough to make their displeasure official.

"This conduct is far removed from the principles of fair play, equality and unity that a football World Cup should represent," Ecuador's federation said in a statement. "We trust that these unsporting acts will not tarnish the football celebration that unites two brotherly countries."

The federation also made clear that Ecuador would "always respond on the pitch" — a pointed message ahead of Wednesday's showdown at Mexico City Stadium, where kick-off is scheduled for 02:00 BST.

Mexico's home fortress

The tie carries significant weight for both nations. Mexico have won all three of their World Cup matches at Mexico City Stadium, making the venue a formidable fortress for the co-hosts. Ecuador, meanwhile, earned their place in the knockout rounds with a shock victory over Germany in the group stage.

The winner of Wednesday's tie could face England, who take on DR Congo in their own last-32 fixture on Wednesday at 17:00 BST. Should both England and Mexico progress, the two sides would meet in Mexico City.

FIFA have been contacted for comment on Ecuador's complaint.