Neymar's move to Paris Saint-Germain was certainly the biggest transfer of the summer, but there's no doubt as to what was the most surprising deal in the window.
Renato Sanches was the hottest property in Europe just 18 months ago, a player hotly pursued by the likes of Manchester United and AC Milan before finally signing for Bayern Munich in May 2016. This weekend, he'll be lining up for Swansea City, a club that was sliding into what appeared to be a relegation battle while Sanchez was getting acquainted with the Bundesliga. It is something of an understatement to say that there were few observers who saw a move like this on the horizon.