When Chelsea want to sign someone, they usually get their man. It was a rare case then, when Roman Abramovich failed in his conquest to sign a young Argentinian star from Atletico Madrid in 2010.
Sergio Aguero was the hotshot striker making a name for himself in LaLiga when the Blues first came calling in 2009 - looking for a future successor to Didier Drogba who could fire the club to a Champions League trophy - but baulked at Atletico's £40million valuation of the forward.
The following summer Chelsea tried their luck again - but the Madrid outfit wouldn't budge, and neither would the west Londoners, who were only willing to stump up £30m - with the player's agent demanding a £5m fee on top.