Manchester City have apologised to Chelsea for a song played at the end of their game.
When City finished the game as 6-0 winners, the away Blues fans were further humiliated by "One Step Beyond" blaring from the stadium.
It is a Chelsea anthem that is often used by the fans for their own games.
The result against City has heaped pressure on Chelsea boss Maurizio Sarri.
It is unclear if he will lose his job imminently, but he will know that a season that ends without a Champions League place would be deemed a failure.
The Blues are in 6th place in the league, only one point off the top four.