Even a man as addicted to conflict as Sir Alex Ferguson knows there is no point in picking a pre-match quarrel with as civilised and courteous an opponent as Pep Guardiola ahead of Saturday's European Cup final. It is possible to get under Guardiola's skin, as we saw in his exasperated response to José Mourinho's taunts before the first leg of Barcelona's semi-final with Real Madrid last month, but the exchange had only one winner, and it was not the Portuguese provocateur.

Perhaps that explains Ferguson's sotto voce threat to ban the journalist who dared to mention Ryan Giggs at the first of this week's press conferences. Sotto voce, or stage whisper? Was he consciously inserting a bit of grit into the contest, to dispel the possibility of blandness in the run-up to the biggest night of the year? This is, after all, a man who has worked so hard to create a siege mentality that whereas the whole of England – even the whole of the British Isles, given the nationalities of George Best, Denis Law, Pat Crerand, Tony Dunne and Shay Brennan – stood behind United when they faced Benfica in the 1968 European Cup final, four decades later a large part of the country will be cheering for Barcelona, and not just because the Catalan club is held to represent the forces of footballing enlightenment.

History is in the bones of this meeting at Wembley. Two of the three biggest and richest football clubs in the world will be fighting over the most coveted trophy available to them, on the pitch where each of them experienced the euphoric release of winning it for the first time. This, too, is an occasion relished more than any other by the game's connoisseurs.

Only the naive switch on a World Cup final anticipating a feast of football, as last July's disfigured contest in Soccer City confirmed. But when the players of Barcelona and Manchester United walk out to compete for the European Cup, they will be expected to provide football of the highest quality.

That special optimism dates back to Real Madrid's domination over the early years of the tournament, when Alfredo Di Stéfano and his colleagues opened the eyes of a generation to the beauty that footballers could create. Half a century later, the trophy glitters with a lustre imparted by the individual contributions of Eusébio, Johan Cruyff, Gerd Müller, Michel Platini and Marco van Basten.

Human nature and football being what they are, the expectation of quality is not always met. Red Star Belgrade's victory over Olympique Marseille after a penalty shootout in Bari is remembered 20 years later with a shudder, and few outside Italy and England can have enjoyed Milan's win over Juventus at Old Trafford in 2003 or Manchester United's joyless tussle with Chelsea in Moscow in 2008, two sterile games ultimately settled by the same agonising method. Ferguson, who was among the 135,000 at Hampden Park in May 1960 when Real Madrid scored seven goals to Eintracht Frankfurt's three, has a keener understanding than most of the moral requirements that also form an integral part of Guardiola's Barcelona heritage.

Both clubs are acutely aware that the winners will move up a rung in the tournament's all-time table, joining Ajax Amsterdam and Bayern Munich on a total of four wins, below Real Madrid (nine), Milan (seven) and Liverpool (five). At their level, these things matter a great deal. But so do the countless subplots, chief among which must be Ferguson's desire, midway through his 70th year, to take his revenge on the man on the adjacent bench. When Barcelona comfortably defeated United in Rome two years ago, Guardiola had been in the job not quite 12 months. Ferguson will not want another lesson in tactical composure from a man 30 years his junior, however respectful he may be.

United began that last final with an exhilarating charge that produced five shots and a series of nervous errors from Barcelona's defenders in the first nine minutes. Then Samuel Eto'o broke away to prod the ball past Edwin van der Sar and the match was as good as settled a full hour before Lionel Messi looped his cunning header over United's horrified goalkeeper to complete the scoreline in a match that ended with a flurry of yellow cards for the frustrated losers.

Barcelona, it is said, are even better now: more compact, more controlled and controlling, and routinely able to command more than 70% of possession, allowing their skilful players to rest on the ball while their opponents are driven to distraction and exhaustion. A personal belief, close to heresy in the current climate, is that while all this is demonstrably true, the present side lack the extra dimension provided in the last season or two of Frank Rijkaard's time at the Camp Nou by the presence alongside Messi of Eto'o, Ronaldinho and Thierry Henry, whose unpredictability and breakaway pace constituted a pretty useful Plan B.

David Villa and Pedro Rodríguez, Messi's accomplices in Guardiola's current team, are accomplished finishers, their skills finely integrated into the attacking labyrinth created by Xavi Hernández, Andrés Iniesta and Sergio Busquets. But on the rare occasions when the current Barcelona find themselves in a tactical stalemate, they have problems conjuring an alternative approach.

Before Ferguson's players can hope to profit from such a situation, they must first create the stalemate. Lying awake in recent weeks, the manager's principal concern must have been the centre of his midfield. Should he play two men there, with two others wide and two up front, or try a straight match-up with Barcelona's trio? The key figures will be Giggs, a far more effective player now than the one who endured a rotten night in Rome, Michael Carrick, who seems to have recovered some of the qualities that persuaded United to invest £18m five years ago, and Darren Fletcher, a Ferguson favourite for big matches.

Fletcher, whose absence from the 2009 final through suspension was a key factor in United's failure to compete with Barcelona, missed most of March and all of April with a "mystery virus". The 27-year-old Scot returned to play the last 20 minutes of the second leg of the Champions League semi-final against Schalke on 4 May, and was given the whole 90 minutes against Blackpool last Sunday. He seems to have lost weight from his already lean frame, but if he is anywhere near full fitness Ferguson will rely on his driving energy and anticipation of danger to disrupt Barcelona's web-spinning before it gets going. A combination of Carrick, two months away from his 30th birthday, and the 37-year-old Giggs would not appear to present as formidable a barrier to the Catalans. It was good enough to see off Chelsea in both legs of the quarter-final and in the crucial Premier League meeting at Old Trafford a month ago, but Chelsea are not Barcelona.

While Ferguson prefers to add a little spice to his preparations and makes a science of rotating his squad, Guardiola operates in the most serene and stable of environments. Whereas several options of formation and selection are still open to Ferguson, only last-minute injuries would disrupt Barcelona's plans. A lack of self-confidence will not be their problem; an excess of it could be. Even the humblest player might be affected by a couple of years of being told, by the credulous and the sycophantic, that he is a part of the best football team ever put on earth.

If anything threatens the spectacle, it is the habit, common to both teams, of putting the referee under pressure. Viktor Kassai, the 35-year-old Hungarian official, may need to call on almost a decade of international experience as he is surrounded by players – one or two of them older than him – demanding favourable decisions and waving imaginary cards.

This is Wembley's sixth European Cup final, to follow those of 1963 (won by Milan), 1968 (Busby's United), 1971 (Ajax), 1978 (Liverpool) and 1992 (Barcelona). But it is the first at the new stadium, the most expensive ever built to house football, its giant illuminated arch replacing the old twin towers as the venue's signature. With a minimum ticket price of £80, and hospitality suites going for £45,000, the match cannot help but symbolise football's new realities. It is the players who have the chance to uphold older values.