In December 2011, Atletico decided to take a gamble.
Having endured a frustrating campaign under Gregorio Manzano, they decided to appoint Simeone – who had previously worked at Racing, River Plate and Catania.
Atletico were 10th at the time and the Argentine was a risky appointment, unproven and better-remembered for getting David Beckham sent off than anything else during his playing days.
Yet what a decision that proved to be.
Simeone has, throughout his time at Atletico, rebuilt them to become one of the biggest clubs in world football.
He’s won La Liga twice, in 2014 and 2021, ending Real Madrid and Barcelona’s dominance of the top flight in the process.
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Atletico have also claimed the Europa League title on two occasions, too, in 2012 and 2018.
And they also secured UEFA Super Cup victories that year as well, while the Copa del Rey was won in 2013 with the Supercopa de Espana following suit the next year.
Had it not been for Real Madrid, Simeone would also have won the Champions League by now as well.
Los Blancos were seconds away from defeat when Sergio Ramos struck in 2014, with Real eventually winning 4-1.
And they also lost the 2016 final on penalties to their fiercest rivals, too, with Cristiano Ronaldo scoring the winner.
Though Atletico haven’t been their usual selves this season, Simeone is still rightly regarded as a managerial genius.
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So why haven’t United ever come calling?
In 2013, Simeone was still too early into his Atletico Madrid career to leave. Especially with no La Liga title at that time.
Anyway, United were too invested in the idea of hiring David Moyes – who was hand-picked by Sir Alex Ferguson to become his successor.
Then, 12 months later, it was a similar situation.
Simeone had guided Atletico Madrid to the Champions League final but they hadn’t won the trophy. In his eyes, he had unfinished business.
So United, knowing this, hired Louis van Gaal instead.
Two years later, after the Dutchman had failed to guide the club into the top four and despite winning the FA Cup, Van Gaal was axed.
And links to Simeone immediately arose again.
United, however, had other ideas. Ed Woodward admired Mauricio Pochettino but it was made clear Tottenham wouldn’t let their boss go.
In any case, Jose Mourinho was on the market – having left Chelsea months previously following a torrid start to the campaign.
United decided to do a deal with the devil.
It was acknowledged that Mourinho would ruffle feathers but, as a serial winner, he was exactly what they needed to counter the arrival of Pep Guardiola at Manchester City.
Mourinho won two trophies – three if you count the Community Shield, which he does – before losing his job in December 2018.
And when United wielded the axe that year, they initially planned to go after Pochettino at the end of the season.
What’s more, the Argentine was keen to come.
But then, once again, things changed. Ole Gunnar Solskjaer did so well as interim that, in the end, the board decided he was the right man.
Solskjaer lifted spirits and made United attractive to watch again but there was no tactical plan, so it seemed.
Chaos reigned in just about every game.
Yet when it comes to hiring Simeone as his replacement, the Red Devils have no plans to do that.
If he became available, that’s something that could potentially change.
But United are eyeing Pochettino, Ten Hag or Enrique instead. Whether Simeone can show why he’s so elite on Wednesday night ultimately remains to be seen.