Transfer Deadline Day: Every Premier League Club's Best Signing Of The Window
15. Chelsea - Mateo Kovacic
It's not hard to explain why Mateo Kovacic is Chelsea's best signing this summer. After receiving a transfer embargo for two windows, Chelsea are unable to bid on any players. Because of this, the only signing they have been able to complete is the signing of Kovacic on a permanent deal after his season-long loan from Real Madrid came to an end.
Just because Kovacic is their only signing does not mean he is in any way a bad one, however. Despite the quality of Chelsea's midfield with players like N'Golo Kante and Jorghino, Kovacic forced his way into the side and played a vital role in Chelsea's Europa League-winning campaign.
Alongside the arrival of Christian Pulisic, returning from his loan to Borussia Dortmund, there will still be a fresh injection of energy into the squad, even if some of Chelsea's star players like Hazard have headed out the door.