Shortly before 4.30pm this Sunday, Jose Mourinho will emerge from the enormous tunnel at the Tottenham Hotspur Stadium and make a beeline straight for the away dug-out.
Pep Guardiola will be there waiting and you can bet your bottom dollar the Sky Sports cameras will be trained on the scene.
But there will be a handshake and an embrace, perhaps a quick chat and mutual smiles. There will be eye contact and genuine warmth and affection to the greeting, then battle will commence.
There is a genuine warmth and respect now between Pep Guardiola and Jose Mourinho - but there was a very frosty relationship between the two coaches for a number of years
The two can't even manage eye contact during their days at Barcelona and Real Madrid
The once frosty relationship between the two managers who have defined 21st century football more than anyone else has thawed in recent years.
You could say it's a reflection of the way Mourinho's methods of playing the game have gone out of vogue, with his moments of glory now fewer and further between.
While he'd never say it, Mourinho would possibly privately admit that it's the Manchester City boss who continues to have the greatest influence on their coaching brethren.
And in the week Guardiola's City reached yet another cup final, the gap between the two has never been wider. But it wasn't always this way - and nor was the current cordiality between the pair.
Between 2009 and 2012, when Mourinho managed first Inter Milan and then Real Madrid, and Guardiola was at the helm of a spectacular Barcelona side, their rivalry reached heights of hostility rarely seen between two coaches.
But what is often forgotten is that they were friends before. Mourinho and Guardiola were close when they first met at Barcelona in the 1990s.
Guardiola (left) and Mourinho were close friends during their time together at Barcelona
The pair regularly chatted about tactics as they planned their respective careers as managers
Mourinho wins: 5
Guardiola wins: 11
Guardiola was coming to the end of his playing career at the Nou Camp just as Mourinho was going through that remarkable transition from Bobby Robson's translator to tactical influencer.
He then served as Louis van Gaal's assistant and Mourinho bought into Barcelona's way of playing, which seems so unlikely given the teams and tactics he produced later.
The pair certainly spent many hours at Barca's training ground chatting about tactics and Guardiola came to respect Mourinho's analytical way of looking at the game.
Things changed in 2008. Mourinho, by this time a serial champion after successful spells at Porto and Chelsea, was interviewed for the Barcelona job following Frank Rijkaard's departure.
In a Powerpoint presentation to Barca officials in Lisbon, Mourinho actually named Guardiola, at that time manager of Barca's B team, as one of his potential assistants.
But sporting director Txiki Begiristain favoured a move for Guardiola and he got the top job. Mourinho certainly didn't forget the snub in a hurry.
Mourinho went for the Barcelona job in 2008 but was overlooked in favour of Guardiola
Inter Milan boss Mourinho tries to distract Guardiola and Zlatan Ibrahimovic in 2010
With Mourinho rocking up at Inter Milan not long afterwards, it was only a matter of time before their paths crossed in the Champions League.
They were duly paired together in the group stages of the 2009-10 Champions League, with the goalless draw at the San Siro a tactical chess mate and a goalless stalemate, before Barcelona won the return 2-0.
Mourinho admitted afterwards his team had been outplayed: 'We're far from being Barca in terms of individual qualities and profile. They are better than us.
'If you told me that Inter will face Barca in the semi-final, I will accept it already.'
Mystic Mourinho got his wish - the two clubs were drawn together in the semi-finals - and it proved to be his finest hour.
A Barcelona team that had been forced to make the long journey to Milan by bus because of the Icelandic ash cloud went down 3-1 in the San Siro.
The Barcelona squad were forced to drive from Barcelona to Milan because of the ash cloud
There were contrasting emotions in the 2010 Champions League semi-final, first leg as Mourinho's (right) Inter beat Guardiola's (left) Barcelona 3-1 at the San Siro
Afterwards, Mourinho couldn't resist taking a skeleton out of the closet. His Chelsea team had been beaten by Barcelona in the previous season's semi-final after Norwegian referee Tom Henning Ovrebo turned down four penalty appeals.
'A year ago, Chelsea were crying and Barca were laughing with the referee,' Mourinho scowled. 'They laughed because he denied my Chelsea boys their rightful place.'
His comments could have easily backfired, especially when Thiago Motta was sent off just 28 minutes into the second leg.
But in what would become the classic Mourinho 'park the bus' template, his Inter side restricted one of the best club teams of all time to just four shots on target and one goal to reach the final 3-2 on aggregate.
Nobody will ever forget the way Mourinho sprinted across the Nou Camp pitch, arm raised, to celebrate with his players and the travelling Inter fans up in the Gods.
Michael Ballack chases after referee Tom Henning Ovrebo during the controversial Chelsea vs Barcelona Champions League semi-final in 2009
Mourinho's memorable on pitch celebration after Inter beat Barcelona in the 2010 semi-final
'It was the most beautiful defeat of my life,' he said. 'It is a style of blood not skill. We were a team of heroes. It's a pity I could not play because I have got the same blood.'
Inter would go on to beat Van Gaal's Bayern Munich to complete a Treble and Mourinho announced after the final at the Bernabeu that he was leaving to become manager of... Real Madrid.
Now things between Guardiola and Mourinho were going to get really claustrophobic.
They were already being cast as the Yin and Yang of football because of their coaching philosophies. Guardiola favoured a possession-based, high-press, attack-minded approach, designed to excite and entertain, and won legions of admirers all over the world as a result.
Mourinho was more of a pragmatist. It was win at all costs, even if that meant stealing an early goal and then putting 10 men behind the ball to soak up opposition pressure. There could also be a needle and a nastiness about his teams.
Both methods worked, however, with both managers enjoying plenty of success throughout their careers. They just