1) Manchester United 1-6 Manchester City
United’s heaviest ever defeat in the Premier League, Manchester City inflicted an incredible 6-1 win over their neighbours at Old Trafford in their title-winning season of 2011/12. Mario Balotelli scored twice and coined his famous ‘Why always me?’ slogan under his t-shirt, while further goals from Sergio Aguero, David Silva and Edin Dzeko completed a memorable win for Roberto Mancini’s side. Ferguson called it his worst day in management, and it ended up costing them as City won the title on goal difference on the final day of the season.