At best the Confederations Cup has become a guilty pleasure. Ignoring the tournament out of solidarity with the Brazilian people protesting for a fairer society may seem proper, but the sheer entertainment of the football on offer so far has made it hard to abstain. Which is why many folk will find themselves treating this week's appetising semi-finals like cut-price sausages or shirts, and partake while trying not to think about how they were made.

Taken in isolation, the tournament has been interesting and fun. All the participants have helped make it so, with even the two teams who finished with no points, Japan and Tahiti, charming with their effervescence. A spirit of adventure has fuelled most teams, so much so that even Nigeria's Mikel Jon Obi re-emerged as the imaginative playmaker that he promised to become before José Mourinho strapped him into a straitjacket seven years ago. And with the semi-finals serving up one of the fiercest rivalries in South America and a repeat of last year's European Championship final, the most spectacular clashes should be ahead.

It is impossible to mention Wednesday's Brazil-Uruguay match without invoking the pair's meeting of 1950, when the men from Montevideo beat the hubristic hosts in the World Cup final in the Maracanã, inflicting such deep trauma to the Brazilian national psyche that the defeat is still regarded as one of the defining mishaps in the country's history. The media in both countries have alluded constantly to that game ahead of Wednesday's encounter but perhaps the Uruguay manager Oscar Tabárez best captured its relevance when he said: "I'm not going to talk about 1950. We have played each other many times since then and it never made any difference so why should it have any effect now?"

An eminently sensible question even if it is just about conceivable that the perception of Uruguay as recidivist Brazilian party-poopers – their last win against the Samba Boys was 12 years ago but it was a significant match, Luiz Felipe Scolari's first as national team manager – may just infect the home players with a touch more tension. So far, however, this relatively inexperienced Brazilian team has shouldered the already enormous pressure they are under well, which suggests neither manager will waste much time reckoning with hoodoos and whatnot. Each has more tangible concerns to address.

Many Brazilians wonder whether Uruguay will set out to do a job on Neymar. Stifle the brilliant 21-year-old and they will have shut down Brazil's primary font of creativity, especially if Scolari continues to pick Hulk ahead of Lucas Moura and the usually excellent Oscar puts in as jaded a display as he did against Italy, when the effects of playing on a continuous loop for over two years seemed to catch up with the Chelsea youngster.

Subduing Neymar, however, is difficult because, as the Uruguay defender Diego Godín points out, he is elusive and, even if opponents do manage to keep close to him, he has a knack of drawing free-kicks, from which he is very dangerous. "Neymar is an unpredictable player, one of the best in the world," said Godín. "He has speed, dribbling and many goals. And as he is so fast he always takes advantage of the minimal contact."

Uruguay anticipate having to play most of the match on the counterattack and will have been heartened to note that lesser sides than them have found gaps in a Brazilian defence that Dani Alves and Marcelo frequently forsake to go a-gamboling up front. It will be interesting to see how that influences Tabárez's selection and formation. He has altered both continually in recent months – including three times in the win over Nigeria – in an effort to achieve the linked objectives of getting the best out of his gifted attackers and bolstering a midfield whose dynamism is dwindling. If Scolari has shown during this tournament that he has made definite decisions on who and how he wants to play, Tabárez has shown that he is still searching for the right formula. Find it and Uruguay could shock Brazil again.

Cesare Prandelli's hopes of finding the right antidote to Spanish supremacy have been dented by injuries. The participation of their chief orchestrator, Andrea Pirlo, is in jeopardy and Mario Balotelli, who proved himself a magnificent fulcrum to their attack in the group games – powerful, subtle and sharp – has had to go home injured.

The fitness of his Milan strike partner, Stephen El Shaarawy, is still in doubt and if he is not ready for action, then Prandelli may feel the need to deploy the only other centre-forward he has brought with him, Alberto Gilardino. Or he could opt to emulate Spain's Euro 2012 approach and play sans striker, with Sebastian Giovinco and Emanuele Giaccherini, who impressed against Brazil, flitting forward from advanced midfield positions.

Prandelli's usual instincts are to attack but in Italy's last competitive match before this tournament, May's 0-0 draw in a World Cup qualifier in the Czech Republic, he set out solely to contain the opposition and the current spate of injuries, allied to the leakiness of Italy's defence in Brazil so far and the prospect of suffering a repeat of the 4-0 drubbing by Spain in last year's European final, may convince him to try to prioritise solidity.

Even if Prandelli had a fully fit squad, his task would be more difficult than it was last year. Because Spain, far from waning, seem to be getting even better. The enforced absence of Xabi Alonso from midfield appears to have had a liberating effect, introducing more diversity and directness to their attacking at a time when striking options have also been enhanced. Now they inflict torment on opponents either with a thousand short passes or a few rapid salvos. At the same time, just as an under-protected thermal exhaust port left the Death Star at risk, Spain have betrayed more defensive vulnerability than before, with Nigeria, in particular, proving that they leave holes that could be exploited.

So far in this tournament most teams have erred on the side of adventure and if that continues this week, then so should the guilty hijinks.