Why are Brazilian teams so dominant in the Copa Libertadores now?

Ecuadorian club Barcelona beat Fluminense on away goals on Thursday to prevent an all-Brazilian final four in the Copa Libertadores, but they may live to regret it. In next month's semifinal they take on 2019 winners Flamengo, who won their quarterfinal against Olimpia of Paraguay by the crushing aggregate margin of 9-2.

Reigning champions Palmeiras are in the other semifinal, after beating local rivals Sao Paulo in impressive fashion, and the lineup is completed by 2013 winners Atletico Mineiro, who thumped Argentine giants River Plate 4-0 on aggregate.

This was a significant moment for Brazilian teams in the Copa. River won the title in 2018, overcoming Buenos Aires neighbours Boca Juniors, and were just a few minutes away from successfully defending their title until they collapsed late on against Flamengo in 2019. Last year they narrowly lost to Palmeiras in the semism while this year they have gone a round earlier but there was nothing narrow about it.

Indeed, the recent story of River against the Brazilian teams is symptomatic of what has happened to the Libertadores in the last few years. In 2018, there was not a Brazilian side in the final. Now they dominate.

As well as the strong probability of an-all Brazilian final of the Libertadores, there is also the possibility of the same thing happening in the Copa Sudamericana. Athletico Paranaense take on Penarol of Uruguay in one semifinal, while Red Bull Bragantino are up against Libertad of Paraguay in the other.

How has it come to pass, then, that in the course of four years Brazil has become so dominant? It could, of course, be co-incidence. But it feels like something far deeper.

True, there is plenty of grumbling in South America about Brazilian clubs being favoured by refereeing. One hopes this is nothing more than sour grapes and coincidence, although there is no doubt that Brazil has become the main force behind the scenes in the last few years.

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The calendar speaks for that. The first knockout round took place in mid-July, immediately after the Copa America. This is a time when the Brazilian clubs are in full competitive swing, and everyone else is in preseason. It hands Brazil an enormous advantage: rewarding the country for having a club calendar that pays no heed to FIFA dates, and it is all so unnecessary. There is a gap of more than two months between the semifinal and the final. There was no need to play in July.

But, as the quarterfinals over the last two weeks have made clear, the big Brazilian clubs have no need of a favourable calendar, or even (real or perceived) of friendly refereeing. They are looking far superior. In comparison with 2018, they have got much better, and the opposition has got worse.

The vital moment was the appointment by Flamengo of Portuguese coach Jorge Jesus in the middle of 2019. With the domestic season on pause because of the Copa America, he had a rare luxury in Brazilian football: time to train. He also had a squad full of interesting attacking resources.

The Flamengo front four have earned legendary status over the last few years. Strikers Gabriel Barbosa and Bruno Henrique worked telepathically with playmakers Everton Ribeiro and Giorgian de Arrascaeta, tearing apart defence after defence on their way to success in the Copa Sudamericana, Copa Libertadores, Brasileiro Serie A (2) and Campeonato Carioca (3).

But it is worth remembering that before the arrival of Jorge Jesus, Flamengo were not able to find a way to field all four of them together -- something which looks absurd with the benefit of hindsight.

Back in 2018, Brazilian teams were knocked out of the Libertadores one by one because they did not want to play. Stifled by an excess of caution, the model was strictly low risk and in the big away games they played a deep defence and looked to launch sporadic counter attacks. It was the outcome of a closed football culture, lacking the input of new ideas, in which the dominant emotion was fear. Coaches had no job security, and sought to survive for as long as possible with low-risk pragmatism.

But this made no sense in the Libertadores. The Brazilian clubs had -- and still have -- a massive financial advantage over their continental rivals. They had deeper squads, with far more quality. This year, even surprise packages Fluminense had a bench full of international strikers and playmakers -- including Abel Hernandez of Uruguay, Raul Bobadilla of Paraguay and Juan Cazares of Ecuador. Most of their rivals could only dream of having that kind of firepower on the pitch, let alone waiting in reserve.

With more money and more resources, it made sense to show more courage, to choose a model of play designed to impose an attacking game on weaker rivals. Flamengo under Jorge Jesus showed how to do this in 2019, when he unleashed his fabulous four, and the message has been seen and understood by others.

Palmeiras were a very pragmatic side when they won the 2020 Copa Libertadores. It may have been the best strategy in the punishing calendar caused by the COVID-19 pandemic. The subsequent Club World Cup cruelly exposed their limitations as they finished fourth behind Bayern Munich, UNAL and Al Alhy, but they are now looking more expansive, with a wider attacking repertoire.

For their semifinal, Atletico Mineiro should have former Chelsea and Atletico Madrid striker Diego Costa ready to form a fearsome strike partnership with the rejuvenated Hulk -- albeit with the pair having a combined age of 67. The squad shows another interesting change in the Brazilian game: improved scouting across the rest of the continent. Their lineup includes Jefferson Savarino of Venezuela and Eduardo Vargas of Chile, while three of the four goals against River were scored by Argentines (one from former River idol Nacho Fernandez, and two from ex-Racing midfielder Matias Zaracho.)

The big Brazilian clubs have become more open-minded to new, more attacking ideas of play and to players from other nationalities. They have also found a successful transfer formula: snapping up older players anxious to come home and round off their careers after playing in Europe, or younger ones who have not lived up to expectations in Europe but still have much to offer.

All of this is far more than the rest of the continent can cope with, because while Brazilian club football has been progressing, much of South America is moving in the other direction.

A key development here is the rise of Major League Soccer, and the excellent scouting work its clubs have been doing south of the border. The United States has become yet another destination for South American talent but, so far, Brazil has been relatively untouched. Brenner of Sao Paulo made the move north, along with Talles Magno of Vasco da Gama, but in general the U.S. clubs have been spooked by the higher fees required to sign Brazilian players and have done their shopping elsewhere.

So what now? For the moment it is an amusing novelty to have three Brazilian clubs in the last four of the Libertadores but, given that this looks like being a long-term trend, there must be doubts as to whether the competition can retain its interest? After all, Brazil already has a league and a high-prestige national cup.

Will the Libertadores merely duplicate these competitions? Or might Brazil's domination of the Libertadores give a push to another project: the quest to establish a genuine Pan-American competition, featuring the best from South America, Mexico and the United States?