Memorable transfer swaps: David Luiz from Benfica to Chelsea
Luiz's transfer is among Four For Two's 10 best swap deals in football history.
Nemanja Matic + £20m for David Luiz
Chelsea's policy of hoarding every promising youth player does lead to some odd transfer dealings.
The Blues traded no-nonsense midfielder Matic for centre-back Luiz in 2011, who had been a key player for Benfica, but is very much the opposite of Matic in every possible way.
Matic would rejoin Chelsea after an impressive spell with Benfica, playing alongside Luiz (who had left to join PSG and then came back) in their Premier League-winning campaign of 2016/17.
Matic is now at Manchester United, while Luiz remains at Chelsea in a much more restrained role than before, which is a pity.