Following his alleged stamp on Liverpool's Emre Can in the second leg of Capital One Cup semi-final and his subsequent retrospective three-game suspension, there's been plenty of discussion about Chelsea striker Diego Costa and his 'edge', as Stan Collymore describes it in his column for Mirror Football.

The former Anfield striker believes that sense of rule-bending aggression should be eradicated from the Spain international's game.

He certainly has a valid point that those sympathising with Costa - such as Gary Neville (although I completely agree with the Sky Sports pundit that Costa's been charged with an unprovable crime) - are the same people who wanted Luis Suarez to be treated with a zero tolerance policy when he was shin-shattering, ankle-nipping, diving and biting for the Reds; although the Chelsea star's antics are yet to reach such outrageous proportions, there is an obvious contraction - and perhaps the FA hope Costa's ban will act as a safeguarding deterrent against his aggression propelling to that level.

Yet, my question is simple - if Costa wasn't a streetfighting, Boardwalk-Empire-faced, physically imposing, rule-breaking No.9, would Chelsea have devoted so much time, effort and money into bringing him to Stamford Bridge last summer?

I'm not suggesting Jose Mourinho spent £32million on a striker in the hope that he'd stamp on someone. Likewise, Costa's current status as the Premier League's top scorer, 17 in 19, and his resulting importance to Chelsea speaks for itself - the Blues' top scorer in the league last year was winger Eden Hazard, with just 14.

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Yet, there are many strikers the west Londoners could have signed last summer that would likely take equal advantage of the incredible service Hazard, Oscar, Willian and Cesc Fabregas have continually provided this season. We know Radamel Falcao, a striker with a career return of 225 goals in 375 appearances, was available, as was then-Bayern Munich's Mario Mandzukic, Swansea City's Wilfried Bony through a £19million release clause, and the aforementioned Cannibal of Merseyside. Even Real Madrid's Karim Benzema and PSG's Edinson Cavani were realistically within Chelsea's financial reach last summer.

But there's something unique about Costa, and that's indeed his streetwise and combative nature. Despite his hot-headed reputation, have you actually ever seen the Spaniard lose control of his emotions in English football? Whilst his antics sometimes veer toward the territory of malicious or snide, it seems to be the opponents - not him - that get riled up.

In the semi-final second leg at Stamford Bridge final, for example, virtually every Liverpool player squared up to him at some point over the 90 minutes, which seemed to affect them considerably more than it did the Blues forward. We saw similar scenes during the Blues 6-3 victory over Everton at the start of the campaign. That's a huge asset for a club like Chelsea, all the more in major fixtures like semi-finals.

He appears to find particular enjoyment in antagonising opponents before punishing them with the simplest of finishes, and in that regard, similarities can be drawn between Costa's methods on the pitch and Mourinho's during interactions with the British press. It's all distractions and smokescreens from the real issues at hand - managers preoccupied with Mourinho's mind-games and defenders with Costa's dirty tricks, when really both should be only concerned with the immense quality Chelsea can punish them with.

Perhaps I'm downplaying Costa's talents slightly; he is, unequivocally, a top-class centre-forward and a lethal goalscorer, blending height, brawn and - often glaringly overlooked - link-up play, creating, on average, 1.7 chances per match this term, with incredible composure in front of goal. He's not been brought to Stamford Bridge to go around 'doing jobs' on people.

That aggression however - those savvily-placed elbows, the heated exchanges of bravado, the alleged 'stamps' - is the integral layer to Costa's game that the rest of it revolves around. Perhaps he could exert more control over it at times but much like Luis Suarez, it's hard to imagine one part of the Chelsea striker without the other. In fact, the Uruguay international has attempted to clean up his act since moving to Barcleona - picking up just one booking so far this season - by adopting a more measured style; his goal record has duly suffered however, netting just twice in twelve La Liga outings, and he's just not the same intense attacking presence as he was at Liverpool.

Indeed, the 'edge' is part of the cosmic balance that is Diego Costa. Approaching football matches like a pub brawl isn't something he's adopted recently - it's the ugly manner in which he's learned to play the beautiful game. That may result in the odd booking or suspension, but without it, the Spain international wouldn't be the player he is today. Consequentially, in my opinion at least, Chelsea wouldn't have invested £32million in him last summer.

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