Argentina and Brazil lead the fall of the Copa América giants

The giants woke up, but only to be felled. When Argentina and Brazil scored seven goals between them in their third group games at the Copa América, it seemed they were slowly rousing themselves for the march to a meeting in the final that the organisers had done everything in their power to make inevitable. In their quarter-finals, though, the problems of the opening games returned. Both struggled to make domination of possession count, both lost on penalties, and both will look on a barely credible semi-final line-up and wonder why on earth they are not there.

Peru had begun a weekend of shocks with their extra-time victory over Colombia, Uruguay and Paraguay continued it with their shoot-out victories over the continent's giants and, as a full moon loomed over San Juan, Venezuela completed a full set of four quarter-final shocks, which seemed almost expected. Restaurateurs and hoteliers in Mendoza will be disappointed to have missed out on another Chilean invasion, while the rest of Argentina wallows in the gloom of another disappointment.

All the Copa adverts on television, featuring a smiling Lionel Messi and a goalscoring Carlos Tevez, feel oddly poignant now.

As Pablo Vignone wrote in Pagina 12, Argentina "paid too high a price" for failing to take advantage of the 20-minute spell in the first half when they were on top. Perhaps they were unlucky to come up against, in Nestor Muslera, a goalkeeper having the game of his life – his save late in normal time, when he kept out Tevez's deflected free-kick with a stretch of his left boot as he fell to his right, and then recovered to block Gonzalo Higuaín's follow-up with a Schmeichel-style star-jump, was exceptional – but Argentina invited disaster.

After Diego Pérez had been sent off six minutes before half-time, the game should have been Argentina's. They were, after all, already on top. But Oscar Washington Tabárez pulled Alvaro Pereira in off the left, reasoning presumably that he could afford to abandon that flank given Messi tucked infield anyway, and left Luis Suárez high up the pitch with Diego Forlan linking to midfield so there was always a goal-threat. As Argentina became increasingly irritated, they committed more and more fouls, to which the referee Carlos Amarilla (Charlie Yellow as his name has been mockingly translated) responded with a flurry of cards. Javier Mascherano was unfortunate in that the foul for which he picked up his second caution was no more than an inadvertent bump to the back of Suárez's calf – Alvaro Rios got away with far worse – but a red card for an Argentinian had felt as though it had been coming for a while.

"We had the dream of winning the Copa, all the more so because we were playing at home," said Mascherano. "In time we'll turn our heads to the [World Cup] qualifiers, but for now we have a great frustration and we are going really badly." That frustration was reflected in the papers, many of whom made great play of the fact that Messi hasn't scored in his last 16 competitive games for Argentina. Messi, though, is the one player who has been largely blameless in the debacle, brilliant against Costa Rica, and Argentina's best player against Uruguay.

Argentina failed to beat Uruguay for three reasons: a level of complacency after Pérez's dismissal; the brilliance of Muslera; and the tactical anarchy Sergio Batista introduced in the second half by bringing on Javier Pastore and Tevez, something that played into Tabárez's hands. Having packed the centre, what he would have dreaded was Argentina introducing width, playing Angel Di María wide, for instance, or encouraging Sergio Agüero or Messi to stick more to their touchlines. Bringing on Tevez, though, merely led to more of the "verticality", the unhelpful direct running of which Batista had been so critical after the draws against Bolivia and Colombia.

"Failure is a strong word," said Batista. "I wouldn't call this a failure." Which makes you wonder what he would call winning only one match of four at home, and that against Costa Rica's Under-23 side.

"The balance wasn't right, but that takes time and work." That the positive signs against Costa Rica weren't illusory was shown by the first half against Uruguay when, aside from their vulnerability to dead-balls, Argentina looked good. The question is what went wrong at half-time, and it's hard to know who to blame for that but Batista.

Ole was perhaps the harshest in its criticism. "It's not a journalistic assignment to demand that Batista be replaced," said its editorial. "It's an obligation."

He, though, has vowed to battle on, insisting that the Copa was only ever about preparation for the World Cup in 2014. The best preparation, though, would surely have been to win the tournament, and so end the 18-year wait for a trophy, clearing away the mood of anxiety and lifting the pressure of trophylessness. The production line will stop eventually; no country can keep on developing the likes of Messi, Tevez, Agüero, Juan Roman Riquelme, Pablo Aimar, Javier Saviola and Ariel Ortega indefinitely; these are generations that cannot be wasted.

Uruguay, meanwhile, tough, dogged and tactically intelligent go on. The concept of "garra" – literally "claw", but combining mental-strength, streetwiseness, courage and perhaps best summarised as "the ability to win" — is perhaps over-discussed, but on Saturday night only one side had it. On the 61st anniversary of Uruguay's 1950 World Cup victory, when they beat Brazil in Brazil, they perhaps felt inspired once again to beat the odds and the hosts. The Uruguayan paper La República gloried in the anniversary. "The ghost of the Maracanã was raised at the Elephants' Graveyard, as July 16 deserved ... Again a stadium was struck dumb."

Uruguay could hardly have imagined their semi-final opponents. Peru finished bottom of World Cup qualifying and lost Claudio Pizarro and Jefferson Farfán to injury before the tournament, but they have been admirably disciplined, with Paolo Guerrero superb as a (very) lone front man. Perhaps they have been imbued with garra by their Uruguayan coach, Sergio Markarián, who once coached Tabárez, at 64 two years his junior, at Bella Vista. . Colombia had given the impression in the group stage of playing within themselves, of doing just enough, but when they needed to against Peru it turned out they had no other gear. They had their chances, Radamel Falcao missing a generous penalty, and Dayro Moreno spanking a drive against the post, but they were undone by two pieces of poor goalkeeping from Luis Martínez.

The favourites kept on falling. Brazil dominated their game against Paraguay but having been denied by committed and intelligent defending and some inspired goalkeeping from Justo Villar, they were beaten on penalties. "You need more than will to win matches," said Brazil's coach Mano Menezes, although he too offered the excuse of preparation for the World Cup. It probably isn't intended as such, but for Brazil and Argentina both to make such a play of preparing for the future does slightly demean their opponents; perhaps after two successive finals between the giants that attitude is understandable, and in that regard at least the absence of the favourites from the last four is probably a good thing.

Whether it signifies the strength in depth of South American football or the lack of quality at the top is hard to say; the pre-emptive excuse Argentina and Brazil offered works. Neymar and Ganso, perhaps, wouldn't have been blooded quite so young had it not been that Brazil, as World Cup hosts, now won't play a competitive match until the Confederations Cup in 2013. Both were inconsistent, impressing only fleetingly, but the bigger problems were at the back.

Daniel Alves's lack of defensive quality was exposed in the group game against Paraguay by Marcelo Estigarribia, and the fact the left-winger was far less effective against Maicon on Sunday only highlighted how poor Alves had been. Estigarribia himself is keen on a move to the Premier League. He spent last season on loan at Newell's Old Boys, with his English agent Barry Thomas suggesting it would cost only around £1.5m to sign him from Le Mans.

In the semi-final, Paraguay face Venezuela, who rode out an astonishing spell of Chile pressure on Sunday night before pinching a winner. The vinotintos took the lead five minutes before half-time as Oswaldo Vizcarrondo met Juan Arango's free-kick with a powerful header, but they were besieged in the second half, Chile twice hitting the woodwork and equalising through Humberto Suazo before another free-kick led to Gabriel Cichero stabbing the winner. The loss of Tomás Rincón to suspension after he was red carded – harshly – after a clash with Jorge Valdivia is a severe blow, but that couldn't dampen the celebrations after reaching the last four for the first time. The president Hugo Chávez tweeted his congratulations from Cuba, where he is undergoing chemotherapy.

After the final round of group games, La Nacíon hailed the return of "pure logic " to the tournament. That disappeared again over the weekend.