Saturday's Manchester derby is the first meeting of Pep Guardiola and Jose Mourinho on English shores but the history between Europe's two top coaches stretches back across 16 matches, seven years and five clubs.
In press-conference warfare, touchline rows and on-the-pitch celebrations, the pair have become the best of enemies in some of European football's biggest fixtures.
This weekend welcomes the latest instalment of the Guardiola-Mourinho rivalry on a new stage. Here, Sportsmail looks back at how it has played out in the past.
Guardiola's Barcelona vs Mourinho's Inter Milan
Meetings: 4; Guardiola wins: 2; Draws: 1; Mourinho wins: 1
Inter Milan 0-0 Barcelona — Champions League, September 16, 2009
Guardiola's European champions dominated at the San Siro but could not find a way around Mourinho's staunch defensive unit in a first battle between these two very different managers.