It was, by miles, the biggest piece of gossip of the January transfer window so far. United fans were sent to sleep dreaming of a player who holds the potential to resurrect their season.
The Guardian asked readers: Is Juan Mata worth £37m?
It was a straight-forward question. But a complicated one that can be considered three ways: is he worth £37m to Chelsea, is he worth £37m to United, and is he worth £37m in today's hyper inflated transfer market?
The answer to the first part is a resounding no way José. This is a player who has started only half of the club's Premier League campaign and has been left out in crunch games. £37m is a considerable amount to reject for a sub.
Then there is the selling to a rivals argument: Chelsea shouldn't show the same reluctance as United displayed in the summer when they refused to sell them Wayne Rooney for any price. With United lingering in seventh place, Chelsea could hand over a vital weapon to be used to take points off their title rivals Arsenal and Manchester City, which could swing the championship race in their favour.
The answer to the second part is quite the opposite. Mata would be doubly as important to United than he is to Mourinho's Chelsea. If Mata can steer the defending league champions into fourth place, the only outcome that would constitute success of 2013-14, then he is undoubtedly worth the fee.
Finally, the third part assesses the player's individual quality, and there is no doubting Mata's credentials. This is a player who has been Chelsea's star performer across the past two campaigns, who has won nearly every trophy in football.
It is a deal that works for all parties. In a climate where Andy Carroll is worth £35m, Fernando Torres £50m, Edison Cavani £55m and - wait for it - Marouane Fellaini £27m, Juan Mata is surely worth £37m.