Manchester United v Manchester City derby more than just a match - it's a battle of ideas

In the blue corner, the man who oversaw a £165 million outlay, the largest ever by an English club in a transfer window.

In the red corner, the comparative penny-pincher who spent a mere £145 million this summer.

Manchester City and Manchester United finished twinned on points last season. Now the neighbours sit side by side in the charts of the big buyers. They are not merely England, but Europe’s two heaviest spenders. Saturday’s derby at Old Trafford could be presented as a celebration of conspicuous consumption, an example of the super-rich showing off.

But when empires collide, so can philosophies. It is easy to present Jose Mourinho and Pep Guardiola as opposites, but they have taken contrasting approaches to buying, ones which reinforce existing reputations. Mourinho seems the pragmatist, the specialist in the short term; Guardiola looks the ideologue, the dreamer driven by principle.

The Catalan has bought footballers to fit his image, the Portuguese players to suit his gameplan. As a rivalry is renewed, it is with a notable difference. Three of Mourinho’s major acquisitions are already pillars of his side: Eric Bailly, Paul Pogba and Zlatan Ibrahimovic.

Three of Guardiola’s pivotal buys in Leroy Sane, Ilkay Gundogan and Claudio Bravo are yet to debut. One of those - winger Sane - picked up an ill-timed hamstring injury, but the German was signed even though City knew he would miss the start of the season.

Three more of his purchases - Gabriel Jesus, Marlos Moreno and Oleksandr Zinchenko - are not even at the Etihad Stadium. The latter two are out on loan while Jesus, a gifted Brazilian, will not arrive until January.

Jesus is 19, Sane 20, John Stones 22. Guardiola has cast his gaze far into the future, probably beyond his own three-year contract. They should peak under his successor. Mourinho may have recruited the 22-year-old Bailly and the 23-year-old Pogba but each has gone straight into his side in a way that only Stones of the City youngsters has done.

The sense is that Mourinho prioritised an immediate impact. In that respect, and while Pogba is the world record signing, Ibrahimovic is the emblematic arrival. At 34, he could be the ultimate short-term signing, and not merely because he has scored four goals in as many games. A record of winning 13 league titles in 15 seasons, even if two were confiscated because of Calciopoli, suggests he can drive United to glory straight away. He will decline at some stage, but Mourinho may have made off with the Premier League crown by then. If he does, it will be at Guardiola’s expense.

Ibrahimovic represents a formidable roadblock to Marcus Rashford’s chances of playing regularly. His acquisition was a practical way of prioritising the here and now. So was Henrikh Mkhitaryan’s, though the Armenian has been seen less than expected. The United newcomer recorded 11 goals and 15 assists in the Bundesliga last season; City's Sane eight and six respectively. One represents pedigree, one potential. Without gambling, Mourinho has played the numbers game. He has gone for the safer bet.

Mkhitaryan is the odd one out among the United arrivals. He is not a giant. Mourinho has made United a taller team. Guardiola, by dropping Yaya Toure and exiling Eliaquim Mangala, Wilfried Bony and Joe Hart, has rendered City a shorter side. He has emphasised the technical, Mourinho the physical. They could prove an imposing, intimidating group. City’s scare tactics will involve passing and pace, not sheer size.

United look configured with the Premier League in mind. City’s focus has been on Guardiola-ising their side, rather than preparing specifically for meetings with Tony Pulis’ teams. Mourinho appears to have entered the transfer market with a realist’s reasoning that most matches are determined in the middle of the pitch and has purchased men designed to be the best centre-back, central midfielder and centre forward at Old Trafford. Guardiola’s fondness for the flanks has been apparent in the acquisitions of no fewer than five players – Sane, Nolito, Jesus, Moreno and Zinchenko – who can operate as wingers. Mourinho has strengthened the spine, Guardiola looked to the sides. The United man is following orthodox thinking, his City counterpart appearing the more leftfield thinker.

Only the goalkeeping department in the centre of the United side has remained untouched; in David de Gea, Mourinho inherited the league’s best. Guardiola dispensed with Hart and brought in Bravo. It was an ideologue’s decision, perhaps an upgrade in terms of shot-stopping, though time will tell, but taken because of a different vision of football.

In contrast, Mourinho has compromised, perhaps in the interests of harmony or because he believes there are short-term gains to be made by persisting with a player of Juan Mata’s talent, even if few imagine the Spaniard is his ideal player. Despite Mourinho’s treatment of Bastian Schweinsteiger, Guardiola looks the more ruthless, but his brutality may be borne of dogma. Perhaps it really is not personal.

All this makes the match a battle of ideas as much as it is two football teams, Guardiola the idealist versus Mourinho the pragmatist.

The City manager is trying to create a better brand of football; his United counterpart is trying to play an existing form of the game better. Whoever prevails on Saturday will do so partly through his buying, but also partly because of his beliefs.