Having shipped just 27 goals and kept 18 clean sheets, no Premier League side had a stingier defence than Chelsea last term. As such, it is widely accepted that a lack of goals up the other end of the pitch was what proved terminal to the club's title challenge.
Jose Mourinho has moved to right that wrong, spending £32m of owner Roman Abramovich's money on Diego Costa, who scored an impressive 36 goals in all competitions for Spanish champions and Champions League finalists Atletico Madrid last season.
Of course, the Spanish international is not the first striker to arrived at Stamford Bridge in the Abramovich era with a big reputation and a hefty price tag. Some have excelled, such as Didier Drogba, but others have failed to live up to the expectation.
By all accounts, Costa has made an impressive start to life in a blue shirt this pre-season, but he will be hoping that he doesn't go on to flop like his fellow five centre-forwards below.
1. Adrian Mutu (2003-2004)
Transfer fee: £15.8m
Appearances: 38 Goals: 10
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The Romanian, who arrived from Parma, flew out of the traps with Chelsea, scoring four goals in his opening three matches. That haul included a brace against London rivals Tottenham Hotspur. His form quickly fell away, though, and he failed to establish a positive working relationship with Mourinho. He was then sacked in October 2004, having tested positive for cocaine during a drugs test.
2. Hernan Crespo (2003-2008)
Transfer fee: £16.8m
Appearances: 73 Goals: 25
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After a largely uninspiring first season in England, Crespo was loaned out to AC Milan in 2004. He returned the following season, though, and went on to score a memorable late winner against Wigan Athletic on the opening day of the campaign. However, while his goal return was respectable, he never truly settled in the Premier League and the Argentine then spent two years on loan with Inter Milan, whom he joined permanently on a free transfer in 2008.
3. Mateja Kezman (2004-2005)
Transfer fee: £5.3m
Appearances: 41 Goals: 7
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The Serbian scored 129 goals in four seasons with PSV Eindhoven, so when Chelsea paid just £5.3m for his signature, it seemed like a steal. Yet, by the end of his one and only season in England, it was Chelsea that appeared to have been robbed. In Eindhoven, Kezman formed a clinical understanding with Arjen Robben, but the Dutch winger's presence at Chelsea failed to help the centre-forward to settle. He scored just four Premier League goals, the first of which was not scored until December.
4. Andriy Shevchenko (2006-2009)
Transfer fee: £30m
Appearances: 77 Goals: 22
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The rumour at the time was that Mourinho did not want the Ukrainian, believing that his best years were behind him and that Samuel Eto'o would be a better fit for his plans at Chelsea. Even so, Abramovich pressed ahead with the deal to sign Shevchenko, but it was soon clear that Mourinho was right. In two full seasons with the Blues, the centre-forward scored only nine Premier League goals. While his effort could not be faulted, Shevchenko was a shadow of the free-scoring player that he was at AC Milan.
5. Fernando Torres (2011-)
Transfer fee: £50m
Appearances: 172 Goals: 45
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In terms of trophies, Torres can point to the fact that he has been a part of a Chelsea side that has won the FA Cup, Europa League and Champions League. But, having shelled out £50m, the club would have wanted much more from the Spaniard. At present, he's found the net just 20 times in the Premier League from 110 outings. Indeed, it is believed that the club would be open to the prospect of parting with the 30-year-old, but they cannot find a buyer that will match his wage demands.
