Humanity seems to have a built-in regard for symmetry. It was what William Blake admired in the tiger and it explains, various surveys have claimed, why certain faces are considered more attractive than others (Denzel Washington and Cate Blanchett, apparently, have the most symmetrical faces in Hollywood). The instinct with football teams and formations has always been to set them out symmetrically – a 4-3-3 with the shuttling players neatly flanking the anchor and the wingers placed precisely on their touchlines, or a blockish 4-4-2 that becomes two lines with a line half the length set centrally atop them.

That's natural: the numerical designations of formations are the fundamentals, crude basics that give a general picture. But it doesn't map reality. It never has: football is far more about balance than it is about symmetry.

Take, for instance, Brian Clough's Nottingham Forest. After they had won promotion in 1977, Clough toyed with the idea of playing a 4-2-4 with Terry Curran on the right and John Robertson on the left. He and Peter Taylor were concerned such an approach might leave them open, and so in a pre-season friendly against Shepshed Charterhouse they replaced Curran with Martin O'Neill, whose tendency was to tuck in and provide a third man in midfield (alongside John McGovern and Archie Gemmill).

Immediately there was balance. Robertson operated as a playmaker on the left, backed up by the experienced defensive left-back Frank Clark. With O'Neill giving an extra layer of protection in the middle, Robertson's lack of defensive covering was accommodated, while Viv Anderson provided attacking width on the right, breaking forward from full-back.

For years that style was almost a default in the English game: one attacking wide midfielder covered for by a narrower, more defensive player on the other flank. Even as late as 1999-00, Sunderland finished seventh in the Premier League with Nicky Summerbee as a bona fide winger on the right, balanced by Stefan Schwarz tucking in on the left and Michael Gray overlapping from left-back. But how to you denote it? As a 4-3-3? As a 4-4-2? It's both and neither, somewhere in between.

Or take England under Fabio Capello in qualifying for the World Cup. It's in breach of the Rustenburg protocol to say anything positive about the Italian, of course, but as they hammered Croatia twice and scored seven more goals than any other European side in qualifying, England were genuinely impressive. Capello even solved the twin problems of the lack of left-sided players and previously intractable Gerrard-Lampard conundrum (which has become such a potent symbol of England's malaise that, after I'd interviewed the former Brazil goalkeeper Valdir Peres on Saturday, he set down his coffee cup and said, "But before you go, tell me, why can Gerrard and Lampard not play together?")

He played Gerrard on the left of a 4-2-3-1, his natural tendency to drift infield compensated for by the fact that Wayne Rooney often drifted left to replace him on that flank, and by Ashley Cole's forays from left-back. Theo Walcott or Aaron Lennon, meanwhile, provided genuine width on the other flank. (The major tactical problem at the World Cup came because Rooney's role had changed at Manchester United, from support striker to out-and-out centre-forward, and he seemed to struggle to readapt to the deeper position so played too close to Emile Heskey. In turn that meant Gerrard came too far infield, and so England ended up with a bus queue down the middle of the pitch.)

The classic Brazilian 4-2-2-2, similarly, usually involves one of the attacking midfielders pulling out to one flank, and the support striker playing a little to the other side of the main striker, ideally on the side on which the more attacking full-back plays. When Santos won the Libertadores last season, for instance, they had Neymar pulling left off Ze Eduardo with Elano shuttling on the right to provide cover.

Still, even allowing for the fact that an asymmetry is built into Brazilian football, the system Vasco da Gama set up with against Alianza Lima in the Libertadores last week was extraordinary. The back four was orthodox enough: Fagner at right-back, the elegant Dede and Rodolfo at centre-back and Thiago Feltri at left-back. Eduardo Costa and Nilton sat in front of the back four, with the former Lyon midfielder Juninho creating the play just in front of them and to the right. So far so normal. But the front three featured Barbio, an out-and-out winger more blessed with pace than technique, on the right, Alecsandro as a centre-forward and then Diego Souza tucked just behind him and fractionally to the left.

The result was that every attack came down the right. The first half felt like an endless loop of Juninho drifting into space and laying a pass outside him to Barbio, a lopsidedness compounded by the fact that Fagner is a far more attacking full-back than Thiago Feltri. A better side than Alianza – or at least one less torn by disputes over unpaid wages — would surely have been able to check Vasco with relative ease.

As it was, Vasco, having conceded a ludicrous first goal as Rodolfo missed a long clearance, dominated utterly. Even then, they were being held 1-1 when, three minutes into the second half, Giancarlo Carmona picked up a harsh second yellow for a supposedly deliberate handball in the box. Alecsandro struck the bar with his penalty but the game was turned Vasco's way as the Alianza coach Jose Soto took off the left-winger Jorge Bazan for the defender Edgar Villamarin.

He needed to replace Carmona, of course, but removing Bazan simply opened up the flank Vasco were favouring anyway, something Soto tacitly acknowledged when, 13 minutes later, he then took off the centre-forward Jonathan Charquero for the left winger Joazhino Arroe.

By then, though, Alecsandro had had an effort cleared off the line, Juninho had hit the bar and Dede had headed Vasco in front.

Vasco ended up missing another penalty before Juninho, taking over from Alecsandro, converted their third spot-kick of the game, before a late Walter Ibanez goal made it 3-2. Vasco should have won much more comfortably, but the lopsidedness of their play raises concerns for the stiffer challenges to come – such as on Wednesday against Libertad in Asuncion.

Symmetry isn't essential in football, but balance is.