Hello nemesis, old friend. For Brazil and Argentina, the Copa América quarter-finals feel as if they are playing out of a series of psychodramas in which they must face both an old enemy and their own greatest neuroses and failings. Paraguay and Venezuela may have nothing like their long-term history of success, but they do have recent history of causing the giants problems.

For the third regular Copa América in a row, Brazil will meet Paraguay in the quarter-final (at the bonus Centenario edition in 2016, neither side made it out of the group.) One is the most successful nation in World Cup history, the other has never got beyond the last eight; one has won five Copas América in the past 30 years, the other has not won it in 40; one boasts as its most-capped player the three-times World Cup champion and Champions League winner Cafu, the other the former Sunderland centre-back Paulo da Silva. And yet Paraguay eliminated Brazil in both 2011 and 2015.

Copa América: where the quarter-finals will be won and lost Read more

Eight years ago Neymar arrived at the Copa América having just helped Santos to the Copa Libertadores. He was 19 but already being hailed as the brightest emerging talent from Brazil in four decades, the new Pelé waiting to be crowned. But everybody has a gilded future until they get kicked in the air by a Paraguayan. Deployed at right-back as a special welcome in the group stage was Darío Verón, a gnarled 30-something centre-back in the great Paraguayan tradition. The look of shock on Neymar’s face when Verón first clattered him still resonates, the horror of a player cosseted at home suddenly discovering that the rest of the world had no interest in easing his passage to the pantheon.

A last-minute equaliser meant Brazil got away with a 2-2 draw but they then faced Paraguay again in the quarter-final. It was a similar story, only this time it finished 0-0. An ineffective Neymar was withdrawn in the second half for Fred who, as his side disintegrated, ended up being the fourth Brazilian out of four to miss from the spot as they lost the shootout.

Four years later, everybody had worked out Brazil could be rattled if you kicked them (or, more accurately by then, if you kicked them back.) By the time they faced Paraguay in the last eight in Concepción, they had already lost Neymar for the tournament after he abused a referee following a petulant red card in a ferocious group game against Colombia. Brazil took the lead but were rattled by Paraguay’s physicality and again ended up losing on penalties, their soft centre exposed.

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This is not the same Paraguay. Eduardo Berizzo has been appointed to try to modernise their football in the same way he, as an assistant, helped his great mentor Marcelo Bielsa reinvent Chile a decade ago.

The prospect of a high-tempo, high-pressing game married to Paraguay’s habitual tenacity is appealing but the evidence of the group stage is that they remain a work in progress. They pose more of an attacking threat than in the past but with enhanced creativity has come greater vulnerability.

Whether this is the same Brazil is debatable. Tite is an admirably calm manager but public opinion has started to wonder whether he may be a little cautious. The 5-0 win over Peru in the final group game was perhaps not as emphatic as the scoreline suggests: although Gabriel Jesus revelled in his right-sided role and Brazil played extremely well in the second half, their fluency came only after being presented with two early goals. Paraguay will not be so generous and if there is any hint of self-indulgence about Brazil, Paraguay, even in this evolving form, are the ideal side to expose it.

Facebook Twitter Pinterest Argentina’s Juan Foyth, left, and Milton Casco, right, take part in a teqball game. Photograph: Mauro Pimentel/AFP/Getty Images

How Argentina would love their biggest problem to be wondering whether a 5-0 victory was really as convincing as it appeared. Under Lionel Scaloni, who has used 40 different players during his 12 games as a caretaker, they are a blind man in the fog blundering about with only the vaguest sense of which direction they may be heading.

Venezuela have beaten them only twice in 25 previous meetings and yet so bad have things become that La Nación this week ran a piece under the headline “Argentina has much to learn from the Venezuelan revolution” (it was referring, it should be made clear, to football, a beacon of consistency amid the political chaos.) Rafael Dudamel was named Venezuela coach in 2016 while continuing to serve as the under-20 manager, a position he had taken the previous year. In that time, Argentina have been through seven under-20 coaches and four senior national coaches, with little of any sense of collaboration between the roles.

This will be Dudamel’s fifth game against Argentina and the first time he has met a coach for the second time. His previous game against Scaloni’s Argentina came in a friendly in Madrid in March and was won 3-1.

Facebook Twitter Pinterest Venezuela prepare in Rio de Janeiro for their meeting with Argentina. Photograph: Carl de Souza/AFP/Getty Images

Just as Paraguay’s qualities highlight Brazil’s greatest weakness, so Venezuela’s consistency and coherence – Venezuela’s! – exposes the shambles of the Argentinian game. The grandees should be feeling very nervous.