Chelsea – Enzo Fernandez (€80m)
Chelsea invested a huge sum of money when the Argentinian international joined from Benfica in January.
A club record £107m transfer fee is a lot to live up to and it remains to be seen whether Fernandez meets expectations.
The 22-year-old has, arguably, not been deployed in his favoured position during his time at the Blues so far, having been asked to play as a no.6.
We should get a better gauge of his performance levels at the start of his first full season in England.