Kylian Mbappe's move to Paris Saint-Germain has been named the worst-value deal of the transfer window, with Liverpool's purchase of Mohamed Salah ranked as the best.
According to an analysis of a record-breaking summer transfer window by CIES Football Observatory, Mbappe's loan from Monaco - which will be made permanent for €180million (£164.5m) - saw PSG overpay by €87.4m.
An algorithm is used to "scientifically estimate fair transfer values" and also deemed Barcelona to have parted with €51.2m more than Ousmane Dembele is worth.
At the other end of the scale, Liverpool landed Salah for €19.4m less than his €69.4m worth. Chelsea's €54.2m (£49.52m) purchase of Antonio Rudiger was €15.2m (£13.9m) less than the defender was worth.
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Despite their success with Salah, Liverpool overpaid by the tune of €12.9m (£11.8m) to take Alex Oxlade-Chamberlain from Arsenal.
Elsewhere, Tottenham are stated to have squeezed €14.7m (£13.45m) more out of Manchester City than Kyle Walker is worth and Crystal Palace overpaid by €22.9m (£20.94m) for deadline-day signing Mamadou Sakho.
The algorithm has decided Everton overpaid by €52.7m (£48.2m) for Jordan Pickford and Gylfi Sigurdsson alone.
