In our Transfers that shook the club feature, Football Transfer Tavern takes a look at deals that many may not have seen coming and the impact that they had during their time by using statistical data and pundit remarks.

Certain transfers can have the ability to put a football club on the map and make the rest of the football world (or at least, domestically) take note of just what their aims and ambitions are moving forward. Chelsea certainly looked to do that in 2003.

Having been taken over by Russian billionaire and business oligarch Roman Abramovich in the summer of 2003 (BBC), the club looked to turn themselves into one of football's powerhouses as quick as possible and splashed the cash as if it were going out of fashion in the imminent future.

Indeed, as per Transfermarkt, sheer volumes of cash were spent on signing the likes of Damien Duff, Juan Sebastian Veron, Joe Cole, Wayne Bridge, Scott Parker, Adrian Mutu and Claude Makelele (to name a few as we'd be here all day otherwise), however there was, perhaps, one addition that signalled Chelsea's intent to take on some of the best in world football.

The Blues managed to land themselves, arguably, one of the best strikers in the game at the time in Hernan Jorge Crespo for a fee of just £16.8m (BBC) as Abramovich looked to send a message to those watching.

The Argentina international had been extremely prolific during his time at Parma (94 goals in 201 appearances) and SS Lazio (48 in 73 matches) prior to his move to England, which would have left to some confidence that the South American could fire them to glory.

Crespo did not start life too badly in SW6, as he managed to net 12 times in 31 appearances in his first season at Stamford Bridge (Transfermarkt), although the arrival of Jose Mourinho and Didier Drogba effectively curtailed his career in the capital.

After a spell back in Italy, the forward was given a chance to prove his worth under the Portuguese manager and helped the club retain the Premier League title with ten goals in his 30 top-flight appearances (Transfermarkt), but was subsequently moved on shortly after.

Crespo recently admitted he had unfinished business at the Blues and felt that he could have, perhaps, offered a little more if given the time. Speaking with FourFourTwo, he said: "I wanted to give something back as I felt I had their respect. I had fun with Chelsea. I would run all the way there if I had the chance to go back".

Whilst there is, perhaps, a sentiment that the Argentine was considered a flop at Chelsea, it might be a little misguided as 90min.com suggests - as they point out that he managed to score 20 goals in 49 league appearances during his time at Stamford Bridge - although he does have a certain 'cult hero' status (per Planet Football).

One thing that cannot be debated, though, was that Crespo's arrival paved the way for some of the club's big-name signings after him and helped put Chelsea on the transfer map as a place that meant business when it came down to things all on the field.

Chelsea fans, do you think Crespo's addition made clubs start to take notice of the Blues? Let us know your thoughts by sharing them in the comments section below!