The transfer of Adem Ljajic could turn out to be one of the most important in recent football history.
Ljajic, who grabbed 13 goals to help Fiorentina finish fourth in Serie A last season, made an €11m switch to Serie A rivals Roma early on Wednesday afternoon.
Even in this age of constant, instantaneous news, the transfer was met with little fanfare outside of Italy. Yet, it could act as the catalyst that sets in motion an astounding few days of transfer activity before the window shuts.
It is pretty much common knowledge that barring an absolute catastrophe Gareth Bale will be a Real Madrid player by next Monday.
By nature a transfer window is littered with conjecture, but the deal for Bale to move to the Spanish capital is said to have been in place for some time now - with the tenuous non-updates beginning to resemble some sort of self-parody, but, for good reason, the deal has yet to be ratified.
That reason could very well be Ljajic.
Augmented by the appointment of Franco Baldini, Tottenham run a tight transfer window ship and wanted to replace - or at least attempt to replace - Bale before they sanctioned the world record move.
And, while they had already signed well this window, they were yet to sign a player in the mould of Bale but Roma's capture of Ljajic immediately changed that, as it allowed the Rome club to approve the sale of Erik Lamela to Spurs for €30m.
That capture should finally see the Bale move completed, which could herald a transfer scramble as Real begin to clear their decks, and the domino effect could have ramifications across Europe.
The much-maligned transfer activities of Tottenham's great rivals Arsenal were expected to receive an immediate fillip from said domino effect, but Karim Benzema, Angel Di Maria and Mesut Ozil quickly ruled out moves to the Emirates - or, more accurately, away from the Bernabeu.
This is where the conjecture returns. Even Madrid need to balance the books and particularly with Financial Fair Play on the horizon. Prior to the almost-certain Bale capture, Real had spent €63.8 million on Asier Illarramendi, Isco, Daniel Carvajal and Casemiro, and the man who may end up balancing those books could, almost inexplicably, be Cristiano Ronaldo.
The rumour mill has been in overdrive since the Portugal captain said that he was "sad" at the Bernabeu in September 2012 - and with Bale set to supersede his status as the world's most expensive player, the 2008 Ballon d'Or winners' ego may not allow him to share a changing room with the latest galáctico.
And in step Manchester United.