There's been an unusually high level of business between the Premier League's top clubs so far this summer, but no transfer has raised eyebrows more than Chelsea's decision to sell Nemanja Matic to Manchester United in a £40million deal.

Decent money for a defensive midfielder who will turn 30 before the start of next season, perhaps. But Chelsea have also handed over arguably the best defensive midfielder in the Premier League and the perfect player to take Jose Mourinho's Manchester United one step closer to being a title-winning side - in fact, it's the exact signing the Portuguese made in January 2014 to transform Chelsea from also-rans into a ruthless winning machine.

Just one Premier League game into his United career and we've already seen how important the Serbian international is in the engine room, providing the necessary physicality and defensive protection to give more attacking license to the players around him, particularly Paul Pogba who, despite technically lining up alongside Matic in a midfield two, still found the freedom to make six dribbles, create two chances and get on the scoresheet in the last minute.

Matic himself produced an incredibly assured display, actually outperforming Pogba for dribbles whilst demonstrating the vast control he gives United in the middle of the park with two tackles, four successful aerial duels and the most passes and most touches of any Red Devils player.

We're just one game into the new campaign but Matic is already making a strong case for himself as the signing of the summer; whereas United struggled for that defensive presence in midfield and goals last season, they've started 2017/18 with an incredibly convincing 4-0 win, the 6 foot 4 midfielder serving as the backbone.

It makes Chelsea's decision to sell a player so crucial to their last two Premier League titles and so openly adored by Mourinho all the more baffling. Perhaps Tiemoue Bakayoko's form will soon vindicate it, but the Frenchman already has some catching up to do on Matic.

https://video.footballfancast.com/video-2015/PL25(10-11).mp4