Jadon Sancho's phenomenal rise at Borussia Dortmund certainly induces at least a trace of regret at Manchester City. 

The jet-heeled winger has been a revelation in Germany and last Saturday he became the quickest player in history to reach 50 Bundesliga assists by teeing up Mahmoud Dahoud in Dortmund's 3-0 win over Arminia Bielefeld. 

Following his meteoric rise at club and international level, Sancho is now worth a whopping £90m, per Transfermarkt, though his valuation actually peaked at £117m in March 2020.

That current £90m figure makes him the 2nd most valuable player in the Bundesliga and the 10th most valuable on the planet. 

It's worth remembering that Sancho is still only 20 years old, and this is merely the beginning of a stunning career at the apex of European football.

But is Sancho's exit from the Etihad Stadium the most unsuccessful sale overseen by a Premier League club in the last five years? 

Well, according to a study conducted by BettingOdds.com, it's not. 

The betting website have consulted figures from Transfermarkt to establish which sale has been the most regrettable for all 20 Premier League outfits. 

By comparing the difference between the figure received for a player and their current Transfermarkt valuation, the study has revealed that Chelsea's sale of Mohamed Salah is the most unsuccessful sanctioned by any of England's top flight clubs in the last five years. 

Mo Salah

Liverpool's talisman was offloaded for a fee of just £13.5m in 2016 but he's now worth £108m.

That creates a difference of £94.5m, eclipsing the £82.95m contrast between Sancho's current valuation and the fee City sold him for. 

Sadio Mane and Serge Gnabry have both soared in valuation since leaving Southampton and Arsenal respectively, and they occupy third and fourth places on the list as a result. 

Elsewhere, Mikel Merino has gone on to realise the glowing promise that underpinned his hit-and-miss season at Newcastle United and is now valued at £25.2m more than the Magpies sold him for.

The Spanish technician has been a revelation at Real Sociedad and is likely to feature for Spain at Euro 2021.

Croatian playmaker Nikola Vlasic, former Manchester United flop Memphis Depay and Dominic Calvert-Lewin are some of the other headline names on the list. 

Take a look at every Premier League outfit's most unsuccessful sale in descending order:

20. Max Meyer (Crystal Palace) - Amount received from sale: £0m Value of player now: £2.7m Difference: -£2.7m

19. George Saville (Wolverhampton Wanderers) - Amount received from sale: £0.51m Value of player now: £3.6m Difference: -£3.09m

18. Caleb Ekuban (Leeds United) - Amount received from sale: £0.9m Value of player now: £4.95m Difference: -£4.05m

17. Jonny Evans (West Bromwich Albion) - Amount received from sale: £3.6m Value of player now: £9m Difference: -£5.4m

16. Sébastien Haller (West Ham united) - Amount received from sale: £20.25m Value of player now: £27m Difference: -£6.75m

15. Jeff Hendrick (Burnley) - Amount received from sale: £0m Value of player now: £8.1m Difference: -£8.1m

14. Jan Vertonghen (Tottenham Hotspur) - Amount received from sale: £0m Value of player now: £9m Difference: -£9m

13. Mathias Normann (Brighton & Hove Albion) - Amount received from sale: £1.53m Value of player now: £11.7m Difference: -£10.17m

12. Nikola Vlasic (Everton) - Amount received from sale: £14.13m Value of player now: £27m Difference: -£12.87m

11. N'Golo Kanté (Leicester City) - Amount received from sale: £32.22m Value of player now: £54m Difference: -£21.78m

10. Mikel Merino (Newcastle United) - Amount received from sale: £10.8m Value of player now: £36m Difference: -£25.2m

9. Memphis Depay (Manchester United) - Amount received from sale: £14.4m Value of player now: £40.5m Difference: -£26.1m

8. Moussa Dembélé (Fulham) - Amount received from sale: £0m Value of player now: £27m Difference: -£27m

7. Adama Traoré (Aston Villa) - Amount received from sale: £7.43m Value of player now: £36m Difference: -£28.57m

6. Dominic Calvert-Lewin (Sheffield United) - Amount received from sale: £1.62m Value of player now: £40.5m Difference: -£38.88m

5. Luis Alberto (Liverpool) - Amount received from sale: £3.6m Value of player now: £45m Difference: -£41.4m

4. Serge Gnabry (Arsenal) - Amount received from sale: £4.5m Value of player now: £63m Difference: -£58.5m

3. Sadio Mané (Southampton) - Amount received from sale: £37.08m Value of player now: £108m Difference: -£70.92m

2. Jadon Sancho (Manchester City) - Amount received from sale: £7.05m Value of player now: £90m Difference: -£82.95m

1. Mohamed Salah (Chelsea) - Amount received from sale: £13.5m Value of player now: £108m Difference: -£94.5m