So why did Atletico Madrid spend £57m to bring Diego Costa home? A last tilt at European glory is all you need to know

Should he meld with Antoine Griezmann, an ascendant superstar who may well be in his last season at Atletico, the club's best chance for winning the Champions League is now

Diego Costa has finally returned to the club where he first made his name (Getty)

Would he be here? Would he wave? Would they boo? Would he behave?

In the end all of those Diego Costa questions were redundant. The former Atletico hero turned Chelsea hero turned Atletico hero once again was at the shiny Estadio Wanda Metropolitano but did not, as agreed between the clubs, make a big show of his return.

To play it down in such a fashion, though, belies the significance of this transfer to the people that matter at Atleti.

Chelsea were willing to part with Diego Costa and made that abundantly clear in Antonio Conte’s now infamous text message. You wonder how much a simple SMS may have cost the Blues in leverage and financial terms, and it certainly dragged out a saga that was made unnecessarily messy by Conte’s fast fingers.

But the Blues received a £57m fee for a 29-year-old late bloomer who has had some injury problems. It appears a good deal for the Premier League winners and yet Atleti – and particularly Diego Simeone – still feel they got him cheap, because any money is cheap for someone considered priceless.

The extent to which Simeone was desperate to reclaim the Brazil-born forward was made clear in contract negotiations with Atletico over July and August, and before signing a new deal earlier this month he ensured that the deal for Costa’s return – at that point nearly done – would be completed. He had received vague assurances earlier in the summer but, considering a Fifa transfer ban means he can’t play for Atleti until January anyway, the rush to sign him before August’s deadline day was somewhat overblown.

Simeone wants some training-ground time with his new (or should that be old?) player, obviously, and more specifically wants his strength and conditioning expert Oscar ‘the professor’ Ortega to work his usual tricks in preparing the player for the brutally energy-sapping demands of playing in this Atletico team. A tailored programme to coax him back to 100 per cent fitness has been planned out since June in anticipation of the inevitable.

Diego Simeone has been desperate to bring Costa back to Atletico (Getty)

But to understand why Costa means so much to Atletico you need to go back to the early part of Simeone’s reign and Atletico’s ascent. The Argentine took over, let us not forget, with this famous but dreadfully-run old club struggling against relegation in 2011 and the thought of knocking Barcelona and Real Madrid off their perch was laughable.

It was a rise built on defence – and a historically great defence at that – but it was Diego Costa’s arrival from pauper Southside neighbours Rayo Vallecano that propelled Atletico from a cup-winning team (Uefa in 2012, Copa del Rey in 2013 and various Super Cups interspersed) into a league-winning team in 2014.

Infamously, heart-breakingly, there was Lisbon. A last-gasp Champions League defeat to cross-town bazillionaires Real Madrid still leaves behind a venom for which no moral victory has proven an antidote.

To even win La Liga in the era of superclubs, of Lionel Messi and Cristiano Ronaldo, remains one of modern football’s greatest achievements but Simeone – like Costa – is not ready to accept that as their zenith. Not yet, at least.

Atletico have missed Costa's explosive style on the pitch (Getty Images)

Before Costa’s explosion into being an elite goalscorer, Atletico were a team that often struggled to create in open play and that relied on the set-piece and scrapheap goals of Raul Garcia. Costa’s way of leading the line changed Simeone’s team from plucky cup side to a league-winning machine that could rattle out narrow victories but as soon as the leftover cava warmed and the confetti from their title parade was swept away, Costa too was gone, sold by Atletico’s hierarchy in a move pushed for by agents and moneymen.

For football men at Atletico, and Diego Simeone is the ultimate example, it was a devastating blow. If Koke was the head of this Atletico team and Diego Godin was the heart, then Diego Costa was the balls. Losing him stopped this team from reaching greater heights; they lost their spunk and while they have threatened to get back to their peak, they have not quite touched it since Costa left.

Simeone had dreamt of Real Sociedad’s Antoine Griezmann playing alongside or behind Diego Costa and the Frenchman arrived that same summer as part of a big remodelling. He, in the intervening years, has developed into a world-class forward but his rotating cast of partners and foils have all failed in different ways, ending scrunched up in the transfer bin.

Simeone will now have the chance to place Griezmann alongside Costa (AFP/Getty Images)

Mario Mandzukic, Jackson Martinez, Luciano Vietto, Kevin Gameiro and tonight Angel Correa have had their chance but never been the right guy. Fernando Torres is adored but not suited, obedient but not explosive. Atleti have worked their way endlessly through central forwards who could function as a reference point for Griezmann but they have not done so blindly because they always knew what they wanted – principally because they never really replaced him. Griezmann was a 10 who replaced Costa, the 9, but £57m and three years later they now have both.

While Atletico Madrid’s ruthless, sometimes brutal playing style might suggest that they are all business, this is actually a pretty emotionally-driven club. Fernando Torres’ return and subsequent contract renewal is just one example of that and the obsession with Costa’s return was led by the heart while their play is still very much reliant on the head.

Simeone and his trusted assistant Mono Burgos believe that they can continue to put together an impermeable defence and sustained success over recent seasons supports that. But now, with the return of Diego, they have both the defensive solidity that never left and the unstoppable goalscorer that did.

Should he meld with Griezmann, an ascendant superstar who may well be in his last season at Atletico, their best chance for winning the Champions League is now.

If anyone was wondering why this club overspent on an ageing, temperamental forward who went missing this summer, that Atletico can sniff glory on the biggest stage is all you need to know.