In an unprecedented period of dominance, clubs from Brazil have won the Copa Libertadores - South America's Champions League - for the past five years.

In three of the past four seasons they have provided both finalists, and going into this year's semi-finals - with the first legs this Wednesday and Thursday - it could happen again.

The main hope of ending Brazil's stranglehold on the competition comes from Argentina's River Plate - not least because the final on 30 November will be played in their stadium.

Under coach Marcelo Gallardo they were the last non-Brazilian side to lift the trophy, in a famous and controversial 2018 final against great rivals Boca Juniors in Madrid.

After that it was a case of diminishing returns for Gallardo's River Plate, narrowly beaten in the final in 2019, narrowly beaten in the semi-finals in 2020, bundled out in the quarter-finals in 2021 - all to Brazilian opposition - and then out in the second round in 2022.

Gallardo then quit, replaced by former Manchester City defender Martin Demichelis, and again River Plate went out in the second round last year to a team from Brazil.

Former Argentina midfielder Gallardo has since returned and his team are back in the semi-finals, where for the first time in the campaign they face a Brazilian challenge - Atletico Mineiro, who beat them home and away in that 2021 quarter-final.

Coinciding with a late flourish in the career of Ronaldinho, Atletico Mineiro were Libertadores champions in 2013. They have come close in recent years without making it through to another final; the scene is set for two epic encounters, first in Belo Horizonte and then Buenos Aires, between two attack-minded teams.

Once tipped for top European jobs, Gallardo seeks to open out the pitch. Since his return at the start of August he has yet to stamp his imprint on the team, who under Demichelis sought to press and play quick passes through the middle.

They have strengthened the defence with the return from Europe of World Cup winners German Pezzella and Marcos Acuna, but they have struggled for goals. Gallardo has plenty of attacking options though, including Manchester City-bound youngster Claudio Echeverri, who has come of age this year, and former West Ham attacking midfielder Manuel Lanzini.

Atletico have their own highly rated Argentine coach, former Barcelona defender Gabriel Milito.

His side are spearheaded by the front combination of the veteran Hulk, in fine form, and former Bayer Leverkusen striker Paulinho. Left-footed attacking midfielder Gustavo Scarpa, who spent last season with Nottingham Forest, is an important supply line from wide on the right.

After booking their place in the final of the Brazilian Cup on Saturday, Atletico are on a roll.

It could make them victims of their own success - the cluttered calendar of Brazilian football has been a problem for Milito, and there is always a danger of the team running out of gas in the home straight.

But they should have enough in the tank for two potentially enthralling games against River Plate, starting with Wednesday's first leg (01:30 BST).

There is a clear favourite in the other semi-final - and it is not Penarol, although the Uruguayan club are one of the great names of the Libertadores. They were the first champions in 1960, and have won the title five times. The last, though, was in 1987, when young striker Diego Aguirre scored the winner in the final minute. Aguirre is now the coach, and is well aware of the size of the task ahead.

Once football's global market opened up, it became very hard for Uruguayan clubs to compete. Penarol lost the 2011 final to a Neymar-inspired Santos, but otherwise this is the first time for decades that they have gone far in the competition.

Recent Penarol sides have often been full of youth products. This one is more experienced, with the key names - such as striker Maxi Silvera and outstanding attacking midfielder Leo Fernandez - recently brought in. Former Premier League playmaker Gaston Ramirez often brings calm and quality from the bench late in games, and the mix was enough to beat Brazilian giants Flamengo in the last round.

But this one, as Aguirre recognises, will be tougher.

Current leaders of the Brazilian top flight, Botafogo combine a glorious tradition with a dismal recent past. Crippled by debt, the Rio club were becoming all too familiar with the second division until investment from US billionaire John Textor, whose Eagle Holdings also owns Lyon and has a stake in Crystal Palace.

But the rise of Botafogo is not just about money. It is also a tale of magnificent scouting, and good coaching by the Portuguese Artur Jorge, who has seamlessly introduced the new signings.

A few months ago 23-year-old centre-forward Igor Jesus was a relative unknown playing for Al-Ahli in the United Arab Emirates. This month he won his first two Brazil caps and scored his first international goal.

Also on target for Brazil this month was winger Luiz Henrique, in rich form since joining the club from Real Betis. Recent reinforcements include the Premier League full-back duo of Vitinho, formerly of Burnley, and Alex Telles, once of Manchester United, plus Argentina midfielder Thiago Almada.

How long some of these players will stay at Botafogo is an interesting question, but for the moment the club's fans are revelling in a return to the glory days of Garrincha and his illustrious team-mates of the 1950s and '60s.

Botafogo have never won the Copa Libertadores, and will be looking to put that right, starting by building a first-leg lead in front of their own fans on Thursday (01:30 BST).