Here's a fun fact about MANCHESTER UNITED:
Historically, Manchester United's closest rivals have been Liverpool, Manchester City and Leeds United. Currently, most fans see Liverpool as their biggest rivals due to the success of both clubs.
The Liverpool rivalry began during the 1960s when the two clubs were among the strongest in England, and have been competing closely just about every season since. The Manchester City rivalry dates back to the Newton Heath era of the 1890s and has remained fierce due to both clubs being in the same division for much of their history. Whilst based in traditional Yorkshire-Lancashire rivalry, the rivalry with Leeds United began during the late 1960s when Leeds emerged as a top side, and continued through the 1970s and 1980s before arguably reaching its apex when Leeds pipped United to the league title in 1992.