#1 Losing the title to Manchester City (2011/12)
On 13 May 2012, Manchester City won the Premier League in the most dramatic fashion. Roberto Mancini's side trailed Queens Park Rangers 2-1 heading into stoppage time when the unexpected happened.
Edin Dzeko scored a 92nd-minute header to bring the match level at 2-2. About a minute was left on the clock when Sergio Aguero stormed the opposition box and scored the winner with virtually the last kick of the match.
The 3-2 win enabled Manchester City to snatch the title from United’s grasp as the two teams were locked on 89 points. However, City enjoyed a superior goal difference.
This scenario went down in history as one of the greatest Premier League finishes. United fans will surely want that moment buried deep in their memories.