Now that the summer transfer window has drawn to a close, it's time to reflect on the business of all Premier League clubs.

Have they bought well, sold poorly or swapped a bunch of players without making any difference at all?

Well, this article takes a look at Chelsea, who spent no less than £91million this summer on five summer signings, while saying goodbye to nine senior players.

Indeed, it's been a summer of intrinsic change at Stamford Bridge, so we've rated their biggest and most important deals of the summer. Without further ado...

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CESC FABREGAS

Has the Premier League witnessed a better deal this summer than Chelsea's £30million swoop for Cesc Fabregas?

Arsene Wenger passed on the opportunity to re-sign the former Arsenal captain but Jose Mourinho knew it was too good to miss.

The Spaniard has already completely changed the emphasis of Chelsea's midfield, offering them the vital creativity in the deep-lying role that saw them succumb to disappointing results at the hands of Norwich, Crystal Palace, Sunderland, Aston Villa, West Brom, West Ham and Newcastle last season.

The Blues' major failing in these games was unlocking well-organised defences, but Fabregas has already addressed that issue in abundance. He's currently leading the Premier League's assists charts, as viewable below, with four set-ups in just three games:

That includes this incredible assist to Andre Schurrle against Burnley:

There are few midfielders in world football who can match the 27 year-old's quality or the intrinsic service he now provides for the Blues. And at £30million, the former Barcelona star was an absolute steal.

Rating: 10/10

ROMELU LUKAKU TO EVERTON

Romelu Lukaku's permanent departure to Everton could well come back to bite Chelsea in a couple of years' time.

The Belgium international struggled to forge a positive relationship with Jose Mourinho and according to the Portuguese, was unhappy about competing with two well-established strikers in Diego Costa and Didier Drogba for the solitary striking role in the Chelsea starting XI.

But Lukaku's enormous potential remains undisputed - at just 21 years of age, he's already lead the line for his country at a World Cup and boasts 32 Premier League goals. Here's a look at the Toffees target man in action:

//www.youtube.com/embed/oZ9Onh9EAtU?rel=0

That being said, Chelsea got a decent price for their wantaway centre-forward - £28million to be precise. Not bad considering he only ever made 15 appearances for the Blues and never found the net.

Rating: 5/10

DIEGO COSTA

When the world's leading strikers, such as Radamel Falcao, Luis Suarez and Edinson Cavani, are now easily commanding transfer fees in excess of £50million, £32million signing Diego Costa represents fantastic business on Chelsea's part.

Jose Mourinho was continuously eying the Spain international throughout last season as his 36 goals fired Atletico Madrid to the La Liga title and the 2014 Champions League final, and it's not difficult to understand why.

Boasting an aggressive style and a powerful 6 foot 2 frame, the 25 year-old fits the characteristics of the Premier League well. He's even better suited to Chelsea's brand of football, especially under Mourinho, meeting the requirements for the lone striking role perfectly.

It feels dangerous to speak too soon but the Blues may have finally found their rightful successor to Didier Drogba. Costa echoes the Stamford Bridge icon's physical style and appears capable of matching his goal-scoring exploits too.

Indeed, the Chelsea front-man is already heading the Premier League's scoring charts, with four strikes - including a brace against Everton - in just three appearances:

In fact, his overall performance against the Toffees was nothing short of exceptional:

It's early days but Chelsea have found a striker who suits their style down to the ground and has already found his sights in the Premier League. And once again, by modern standards, £32million is a fantastically cheap fee.

Rating: 9/10

FILIPE LUIS

Chelsea's third signing of the summer, and their second import from Atletico Madrid, was £16million-defender Filipe Luis.

The left-back hasn't quite hit the ground running in the English top flight but there's little reason for Blues fans to panic - Jose Mourinho has carried over the backline of Branislav Ivanovic, John Terry, Gary Cahill and Cesar Azpilicueta from last season that conceded the fewest goals of any Premier League defence and claimed the joint-most clean sheets.

That being said, the Luis deal is arguably the worst piece of inward business thus far during Mourinho's second spell at Stamford Bridge. No doubt, the Brazil international is a top defender -just take a look at his statistics from last season:

He's pretty good on the ball too:

But already 29 years of age, the value-for-money of the Luis deal isn't fantastic. The Blues will struggle to sell him on and although he looks likely to become the resident No.3 in west London at some point, Azpilicueta is doing a pretty good job holding down that role for now.

A solid addition to the squad who suits the Jose Mourinho ethos, but Chelsea paid too much in my opinion. Liverpool signed 22 year-old Alberto Moreno for significantly less, which is already looking like a better investment.

Rating: 6/10

LOIC REMY AND DIDIER DROGBA

Amassing a back-up strike-force of proven Premier League quality can never be a bad thing for a combined total of just £10.5million.

Club legend Didier Drogba returned to Stamford Bridge on a free transfer this summer, whilst Jose Mourinho staged a late swoop for QPR's Loic Remy, activating his £10.5million release clause.

At 36 years of age, Drogba is no spring chicken and the Blues can't be dependent on him for goals. But the retired Ivory Coast front-man is a natural taker Mourinho's philosophy and his leadership qualities will be vital in the dressing room.

Likewise, Loic Remy has proved himself to be one of the Premier League's most potent finishers since arriving in England in January 2013. He's gone on to net 20 times in 42 top flight outings, including this sensational goal against Wigan in 2013:

//www.youtube.com/embed/JC7oWD8N_vI?autoplay=1&loop=1&playlist= JC7oWD8N_vI

His pace, versatility and threat in-behind offers Chelsea something vitally different in attack.

Overall, Chelsea's strike-force may not quite meet the sensational standards of Manchester City or Liverpool's from last season. But Drogba and Remy represent great value for money, whilst fitting well into the natural hierarchy of the squad.

Rating: 7/10

FERNANDO TORRES TO AC MILAN

In the latter stages of the summer window, wayward Spaniard Fernando Torres secured a two-year loan move to AC Milan.

After scoring just 20 goals in 110 Premier League appearances for the Blues - a worse return than Danny Welbeck at Manchester United - at this point, most Chelsea fans will simply be glad to see the £50million flop leave.

Torres had become a running joke at Stamford Bridge and the move will do him a world of good too. Here's a look at the Spain international's worst ever misses for Chelsea:

//www.youtube.com/embed/nS8unXUQv9A?rel=0

But the deal will see the entirety of the west London outfit's original investment thrown down the drain. The 30 year-old's contract expires in 2016, meaning that as soon as his San Siro loan deal comes to an end, he'll become a free agent.

Getting one of their biggest and cost-ineffective earners off the wage bill for the next two years can't be a bad thing, but you feel the Blues could have recouped at least a small fee for Torres

Rating: 4/10

DAVID LUIZ TO PSG

Chelsea fans will miss the floppy-haired exploits of David Luiz, and the Brazil international's quality as a footballer remains undisputed. Here's a look at all his goals for the Blues - many of which are absolute stunners:

//www.youtube.com/embed/zR3z4cK7Hwc?rel=0

But the west London outfit simply couldn't pass on PSG's world record-breaking £40million bid for the defender who comes with several intrinsic flaws.

The Blues never really decided whether Luiz was a centre-back or a defensive midfielder, which epitomises why opinions in England are so divided on the now-Parisians star.

His flamboyant, unpredictable nature, although incredibly entertaining, never quite fitted the Jose Mourinho mentality and in my opinion, Chelsea have done well do squeeze so much cash out of the Ligue 1 champions.

Under UEFA's Financial Fair Play laws, Luiz's departure gave Chelsea enormous licence and freedom in the summer transfer market. It also made a poignant statement of how Mourinho builds his side around ruthless efficiency, rather than luxury players.

Rating: 8/10

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