The obvious response to Manchester City hiring the Spaniard is clear...
Indeed, with Louis van Gaal's days all but numbered - it's just a case of how much more misery United are willing to aimlessly suffer - the case for hiring Jose Mourinho as the Dutchman's successor is a strong one.
But, now, with the knowledge Guardiola would be working at United's great rivals - and in the same city! - the money men at Old Trafford must surely know what this could entail.
Hiring Mourinho at Manchester United makes perfect sense from a footballing point of view; even after this season's Chelsea disaster.
Financially, however, the argument is now absolute. And, after all, finances are everything for Man United.
Think about how much interest and how much revenue a Mourinho - Guardiola reunion would draw across the world?
The two are fierce rivals, just as Manchester United and Manchester City are fierce rivals. City can now make their way into the Chinese market and gain more and more popularity.
United would be mad not to respond with the biggest profit-making move there can be.