The two have been feuding since 2008 when Mourinho was in charge at Inter Milan and Guardiola was at Barcelona. Then the rivalry reached a new level (or low depending on how you viewed it) when Mourinho moved to Real Madrid.
Now the two most successful managers in the world will renew their rivalry at the Bird’s Nest Stadium in Beijing on July 25.
It is a strange setting for a Manchester derby, yet somehow appropriate given the global interest in the Premier League and what is sure to be a captivating battle between two vastly contrasting characters.
Mourinho, the pragmatist, schemer and master of the dark arts, will be charged with making sense of the mess left by his old boss Van Gaal.
Guardiola, the reserved advocate of beautiful football, has the challenge of taking City to the next level.
Neither will be short of the funds to succeed in their task. Both have been tasked to win silverware both domestically and in Europe. Watching them try to do it will be pure box office.
This has the potential to dwarf the rivalry between these clubs in the late 60s and early 70s, when City were in their pomp and United had just won the European Cup, and more recently when the noisy neighbors first got under Sir Alex Ferguson’s skin.
The fallout from a mischievous billboard welcoming Carlos Tevez to Manchester when he moved from United to City will be nothing compared to the sparks Mourinho and Guardiola can produce.