There is a video currently circulating on social media which reveals everything about Ralf Rangnick, the godfather of pressing and the man idolised by many managers in the modern game. Manchester United are in for a shock.
Filmed inside the RB Leipzig dressing room during one of his spells in charge of the club, Rangnick is seen calmly but firmly instructing his players at half-time. Bizarrely, he then appears to switch the lights off and yells at them to 'get out'.
After that, he hands his squad a final dressing down to motivate them and sends them on their way. In a nutshell, this is Rangnick. Forceful, fair and immensely driven, he looks the perfect man to breathe new life into United's drifting season.
Veteran Ralf Rangnick is set to take charge of Manchester United until the end of the season
But Cristiano Ronaldo may struggle with Rangnick's press-centred, high-energy style of play
And quite simply, it is his way or the highway. He is warmly labelled as the genius behind gegenpressing, the heavy metal style of play which has helped haul Jurgen Klopp's Liverpool out of mediocrity and back into the big time.
He has a clear blueprint for how his sides must perform, and demands energy from all of his players to make it work. Klopp and Julian Nagelsmann may look at him all starry-eyed, but several players at United will be dreading what lies ahead.
Extraordinarily, the looming appointment looks set to affect Cristiano Ronaldo. The superstar has single-handedly dragged his team-mates into the Champions League knockout stages, but he has been criticised for his lack of desire to press.
Rangnick is known as the 'godfather of the gegenpress' and will turn United into a pressing unit
Under Ole Gunnar Solskjaer, he got off lightly. It is a myth that he does not press at all, but United's previous boss was undoubtedly more lenient and willing to instruct his other nine players outfield to raise their levels to cover up Ronaldo's weakness.
There will be no forgiveness with Rangnick, though. That much is evident in light of comments from the veteran tactician in 2016. According to him, Ronaldo was too old to be considered for a surprise move to Leipzig - and that was five years ago.
Asked by AFP if he would want Ronaldo or Lionel Messi, Rangnick said: 'It would be absurd to think that it could work with them here.
'They are both too old and too expensive.'
Ronaldo has been criticised this season for his unwillingness to track back or push defenders
In his opinion, Ronaldo and his aging body would not have been able to follow his instructions. Rangnick builds his sides around the same fundamentals - quick patterns of play and good pressing - and prefers to use young players for them.
Therefore, the likes of Mason Greenwood, Marcus Rashford, Donny van de Beek and Jadon Sancho are in for an invaluable lesson - and plenty of hard work - but it is Ronaldo who appears to stand out like a sore thumb. Compromise is needed.
A fanatic for scrutinising over statistics and burning the candle at both ends, Rangnick will surely be alarmed by Ronaldo's numbers.
According to fbref.com, the forward has made just 39 'pressures' in the Premier League this season. In comparison, Bruno Fernandes has made 205, Fred has 224 and even Harry Maguire and Raphael Varane have more than Ronaldo.
According to fbref.com, Ronaldo has made just 39 'pressures' in the Premier League this year
In comparison, playmaker Bruno Fernandes (right) has made 205 and will be a Rangnick staple
Breaking down how and when Ronaldo presses, United have been successful in winning back the ball within five seconds of him closing down an opponent on only seven occasions - resulting in a measly 17.9 per cent.
17 of these pressures have come in the final third, with 20 in midfield and two in and around United's penalty area. Damningly, Mason Greenwood - who has been accused of lacking in work rate this term - has closed down 90 times.
Of course, Ronaldo is now 36 years of age and his lack of effort in trying to steal back possession is understandable. There is also the added complication of him being unlikely to change the play style of a lifetime to help Rangnick out.
If there is one tactic not suited to Ronaldo, it is gegenpressing.