Football is not a predictable game. A team can have 20 chances and still lose to a side that musters only one. All a coach can do is manipulate the percentages as best he can in his favour. With that caveat in mind, though, a prediction – in the next decade, no side will win a major international tournament playing an orthodox 4-4-2.

When a good side play with three central midfielders, whether in a 4-2-3-1 or a 4-3-3 (or either of their close cousins, 4‑2‑1‑3 and 4-1-2-3), they will almost inevitably dominate possession against a side playing only two central midfielders. The old defence of a high offside line simply is not as effective as it used to be thanks to the liberalisation of the rule.

Even if the three do not dominate possession, fielding only two central midfelders leaves a side vulnerable if one of those central players pushes forward, a problem that dogged Manchester United in European competition for much of the late 1990s (the defeats to Borussia Dortmund in 1997, Monaco in 1998 and Real Madrid in 2000; the success of 1999 might have been less fraught with a more cautious approach), and could be glimpsed again in the nervy final minutes of the last-16 victory over Marseille.

It was notable that in the first leg of the Champions League quarter-final, as soon as Chelsea switched from 4-4-2 to 4-3-3, so too did Manchester United, matching them shape-for-shape rather than offering numerical superiority in the centre. Nonetheless, Chelsea had much their best spell in that final 20 minutes. Even Fernando Torres looked sharper, drawing a superb save from Edwin van der Sar with a header back across goal, and flicking the ball on for Ramires leading to the incident in which Patrice Evra got away with a foul on the Brazilian on the 18-yard line. This raises the question of why Chelsea have switched to a 4-4-2.

The lesson of Vienna

One of the oddities of Euro 2008 was that Spain played their best football without their top scorer. David Villa got five goals in Spain's first four games, but it was after he was injured 34 minutes into the semi-final against Russia that Spain produced their best stuff. Villa was replaced by Cesc Fábregas, and the extra man in midfield – a switch from 4-1-3-2 to 4-1-4-1 – allowed Spain to pen in Russia's full-backs, Alexander Anyukov and Yuri Zhirkov, who had looked threatening in the opening stages. The change also allowed Torres to operate as a lone forward. He promptly produced his best performance of a tournament in which he had begun to draw criticism as Spain won 3-0, and topped that with his display against Germany in the final.

The lesson seemed clear: Torres is at his best operating alone. He is quick, and so adept on the counterattack, he offers enough physical presence to hold the ball up, and he is intelligent enough in his use of the ball to bring runners from deep into play. He seemed at the time the model of a modern centre-forward. That was how he was used most successfully at Liverpool, which raises the question of why, since he joined Chelsea, he has so persistently been used in a 4-4-2.

Other issues

The formation is not the only problem, clearly. Football is littered with examples of forwards – Ronaldo, Alan Shearer, Michael Owen – who have lost a fraction of pace after a major operation. It is to be hoped that Torres, now 27, is not one of them, but he is discernibly slower than he was 18 months ago. With the European Championship, the Confederations Cup and the World Cup, it is 2007 since he had a proper summer break. Others in the Spain squad, of course, have been subjected to a similarly hectic schedule (although the intensity of the Premier League probably makes those based in England more prone to fatigue), but the combination of tiredness and injury is a debilitating combination – as Andriy Shevchenko found in his days at Chelsea.

Then there is the great intangible of confidence. Coming back from his operation, Torres had a poor World Cup, which perhaps made him doubt his recovery. He needed to return to a calm, stable club where he could feel his way back in to form, but instead he went back to a Liverpool whose ownership was being decided in the courts and where a lame-duck manager was being hammered by fans and players alike. Whatever you think of the rights and wrongs of Torres leaving Anfield, the environment was not helpful to a player in need of reassurance. He was out of form but as in previous seasons, he was expected to be one of the two or three players to drag the team to respectability.

Moving to Chelsea has only increased the pressure. He has again joined a club scrabbling for form, only this time he has done so with the expectation that a £50m price-tag brings, and without any of the goodwill brought by memories of past performances. The journalist Patrick Barclay raised the suggestion last weekend that Torres may prove to be the worst transfer in the history of football and while it would be absurd to write him off this early, that could easily turn out to be the case. The current holder of that title is probably Shevchenko – 47 largely desultory appearances for Chelsea after a £30m move – which suggests lessons have not been learned.

Mourinho's ghost

Money does not bring wisdom. Centre-forwards are glamorous and exciting, and it is understandable that a man who can effectively buy what he wants should acquire too many. Shevchenko and Torres, though, have become to Abramovich what the gold taps were to Saddam Hussein. Since Mourinho's time, Chelsea's squad have been geared to play 4-1-2-3 – something that is particularly true of the midfield. With a holding player, Frank Lampard and Michael Essien have licence to get forward and provide a goal threat from deep.

There has been a slight evolution, in that Mourinho preferred his full-backs to sit relatively deep and operated with genuine wide-forwards in Arjen Robben and Damien Duff, while more modern incarnations have had Nicolas Anelka playing half-wide on the right and the muscular presence of Florent Malouda on the left with much of the width provided by the full-backs. The basic shape, though, remains the same. Luiz Felipe Scolari and Ancelotti have both attempted to change formation; one was ousted and one ended up going back to 4-1-2-3. Perhaps Avram Grant did little management in getting Chelsea to the 2008 Champions League final, but at least he had the wit not to change a shape that worked.

Torres's arrival, though, seems to have brought an edict that Ancelotti must play him and either Didier Drogba or Anelka in the biggest games. That does not suit either forward, and 4-4-2 does not suit the rest of the squad. Lampard needs a holder behind him to be able to make the forward runs that have brought him so many goals. Whether Malouda or Zhirkov plays on the left, with Ramires shuttling on the right, there is a dearth of creative spark. Ancelotti, quite rightly, attacked those players who were trying to win Saturday's game against Wigan single-handedly and called for greater "teamwork", but his real problem, surely, is that the team does not work.

Yes, Torres is clearly anxious to make an impression, score his first goal for the club and stop the clock on his barren period, but even if the whole squad are in form, it is hard to see how the present squad can play fluently in a 4-4-2 (and even if they do, they would probably be too open to win a major competition).

Perhaps the logic is that, at 32, Drogba is nearing the end of his career – although he was a later starter in professional football which may prolong his effectiveness – and Torres is seen as his long-term replacement. Even then, though, as this analysis by Miguel Delaney highlights, Chelsea may not have the players to get the best out of him. Torres is not a Drogba figure who will win high balls; he thrives on through balls and low crosses (and note how his few good moments on Saturday were related to the involvement of Yossi Benayoun). Perhaps Torres is only the first of a flock of signings, but if so it seems almost cruel to have exposed him before the support structure is in place.

If the intention is to build a new team around Torres, it seems a remarkable gamble given there is no guarantee he will fully recover the form of 18 months ago. And if the intention was for Torres to replace Drogba, of course, there should be no compulsion to play him. He could come off the bench, slowly feeling his way into the role he would occupy next season. All of which suggests that Torres is, like Shevchenko, at least in part a vanity signing by Abramovich. That is not good for the player, and it is not good for Chelsea.