Manchester City have lodged an official complaint to Uefa after alleged racial abuse of some of their players during Thursday's Europa League game at Porto.
City won 2-1 at the Estadio do Dragao, but after the game the club revealed that Mario Balotelli had mentioned to officials about chants from the stands.
Team-mate Yaya Touré said: "I heard something. That's why we like the Premier League, it never happens there. Maybe other countries don't expect black players." The tournament organiser, Uefa, said it was still waiting for reports from match delegates.