There is great irony in Chelsea's former opposition scout Andre Villas-Boas being re-hired as manager to transition Chelsea away from the reactive, counter-attacking style fostered by the man he worked under between 2004 and 2006, towards a more positive, possession-based of football - only to fail and eventually lead to Jose Mourinho returning to his beloved club in order to complete the project Villas-Boas started but never finished.
Mourinho has a reputation as a ruthless, defensive manager, while Villas-Boas has a more positive ‘image' as a proponent of attacking football - but both stereotypes are imprecise, probably unfair, and probably closer to the truth when you say something in between. Yes, Mourinho can be incredibly conservative, but the counter-attacking upon which he builds his systems isn't inherently ugly to watch, and at times, it's breathtaking: the sheer pace and precision of which his former Chelsea side, Inter Milan and most impressively, Real Madrid, scored goals from quick transitions is perhaps unmatched.
Villas-Boas, meanwhile, is widely associated with the "Guardiola" school of management, but that betrays exactly why he admires Barcelona - not because of their patient distribution, but because of the way they mix safe, sideways balls with creative vertical passes. Quick, purposeful forward passing is his mantra, and that sounds rather like Mourinho's powerful transitions. It has become fashionable to portray them as opposites, and while that may be true in certain aspects of management, but stylistically, they're quite similar.
At least, that it is in theory, and at both their current clubs you get the feeling that Villas-Boas and Mourinho haven't got their current teams playing the way they would like. In the case of the latter, it's more obvious: Chelsea were shocked by both Basel and Everton, and there's been widespread discussion about the comparative lack of fluency from his new Chelsea compared to the old one.
It's widely accepted that Mourinho wants his new Chelsea to counter-attack in his image, and while that is largely true and corroborated in his approach to games against Bayern Munich and Manchester United, the reality is that for the majority of Chelsea fixtures this season they will dominate possession and have to use a more patient, probing attack. It's not in the games where Chelsea defend deep and play on the break where they've had issues, it's the ones where the onus is on them to control the tempo throughout and break down a deep-lying defence - Fulham and Aston Villa along with Basel and Everton cases in point.
Tottenham, meanwhile, are also being charged with a similar task - a job made more difficult by the necessary integration of the number of new first-team players they signed over the summer with the funds from Gareth Bale. Tottenham needed to replace Bale's greatest asset, his ability to score long-range goals out of nothing, which was Villas-Boas's way of disguising their inability to score against massed defences.
Long-range shooting can be quite literally a hit-and-miss exercise so it was understandable that rather than sign a direct Bale replacement (which might have proved impossible, anyway) they split their funds across a variety of targets. The majority were about reinforcing areas of existing weakness in the squad, but the two Eriks - Erik Lamela and Christian Eriksen - were particularly important additions, as the two players able to break down defences with a tricky dribble or clever pass.
Having seen Tottenham struggle to break down Crystal Palace, Swansea and Cardiff - relying on a 93rd minute winner from Paulinho in the latter and a Soldado penalty in the two former - you feel like Tottenham's final two signings of the summer will be the most important to the ‘new' Tottenham.
So far this season, both they and Chelsea have been guilty of mundane attacking; lots of passing backwards and forwards but none of that incisiveness that Villas-Boas so prizes, and is illustrated as much in the manner of which Tottenham's lone goal wins have been achieved - basically, through penalties - and in the way Chelsea have struggled already with their results.
Mourinho agrees that things have to change. "I don't want to defend as a low block, central defenders playing in midfield or long balls to a lonely striker," he said in a revealing press conference last week. "We want to be proactive."
"I don't like the way Chelsea were playing the last couple of years; the club doesn't like it and we want to change," he said. "We want to play a different style. We want to play a certain style. Not what you are seeing now - we have to look better than that."
The last point is certainly pertinent. Chelsea are currently operating beneath the sum of their parts, as are Tottenham: the clash on Saturday between the two is not only an intriguing battle between the two managers, but also another step in both team's journey towards manifesting their managers ideas into practice.