On this day - December 31, 2011 - Sam Allardyce's Blackburn Rovers pull off a shock away win against Alex Ferguson's Manchester United side.
It was the Red Devils first defeat in the campaign since the 6-1 pummelling at the hands of rivals Manchester City. Alex Ferguson put out a makeshift XI with multiple players playing out of position - expecting a routine win as a nice little birthday present to continue their title defence.
Things got off to a rocky start after a Yakubu Penalty in the 16th minute and a positive result seemed incredibly unlikely when the Nigerian doubled the lead 6 minutes into the second half. Dimitar Berbatov gave United a lifeline with a brace in 10 minutes, scoring on 52 and 62 minutes, but United were unable to unlock the resolute Blackburn defence to get a winner. Instead it was Grant Hanley who grabbed the points for Blackburn Rovers in the 80th minute, leaving Ferguson seething!
Manchester City went on to win their first Premier League title. Despite the win it was curtains for Blackburn Rovers, who were relegated and haven't returned to the top flight since.