Athletico PR defeated Bahia to reach this stage, while Estudiantes got the better of Fortaleza.
Match preview
For Athletico PR, this is fairly uncharted waters in South America's main continental competition, having only once gone further than this stage as the runners-up to Sao Paulo in 2005.
However, Furacao have won the Copa Sudamericana - essentially South America's version of the Europa League - in 2018 and 2021, which has clearly improved their big game mentality and experience as a collective group.
Felipe Scolari, Brazil's World Cup winning boss from 2002, took charge of the club in May earlier this year, and has so far excelled in the role with a 60% win rate. Not only has the 73-year-old taken his new side up to fourth in Brazil's top tier, but they remain in the hunt for both the Copa Libertadores and Copa da Brasil.
The former Chelsea boss will fancy his side's chances of laying down a marker against their forthcoming Argentinian opponents, especially in front of what should be a raucous Arena da Baixada.
Unlike their Brazilian opponents, Estudiantes do have plenty of historical pedigree in this competition, having won the Copa Libertadores for the fourth time as recently as 2009.
Former Manchester United midfielder Juan Sebastian Veron won player of the tournament that season for his performances for Estudiantes, for whom he is now chairman having been involved behind the scenes at the club since 2012.
Ricardo Zielinski is the man in charge of running things on the pitch, though, where performances have gone a little array of late. Just one win in their last eight league matches sees Los Pincharratas lying in 22nd place in the Argentinian Primeira Division's second phase.
As such, the Copa Libertadores has undoubtedly taken priority in terms of dictating Zielinski's side's season as a success or not. They will be hoping to avoid defeat on Thursday before going for the win at home in the second leg.
Athletico Paranaense Copa Libertadores form:
Athletico Paranaense form (all competitions):
Estudiantes Copa Libertadores form:
Estudiantes form (all competitions):
Team News
Athletico PR will be without midfielder Christian Cardoso, who continues to recover from a knee injury.
Forward Pablo, who has scored twice this season, is also a doubt due to a thigh injury.
Scolari must decide whether to utilise the 4-2-3-1 or 3-5-2 formations which he has switched between lately, with the former likely to get the nod given his side's need to secure a home win here.
Estudiantes, meanwhile, will travel without defenders Fabian Noguera and Ezequiel Munoz due to knee injuries.
Forward Mauro Boselli is also ruled out due to a foot problem.
With a draw representing a fantastic result for his side on Thursday, Zielinski is likely to look to keep things tight with a flat back five system.
Athletico Paranaense possible starting lineup:
Bento; Khellven, Santos, Heleno, Abner; Fernandinho, Erick; Canobbio, Bueno, Cuello; Roque
Estudiantes possible starting lineup:
Andujar; Godoy, Rogel, Lollo, Morel, Mas; Castro, Rodriguez, Zuqui; Diaz, Piatti
We say: Athletico Paranaense 1-0 Estudiantes
The hosts come into this match in better form, and we expect them to secure a narrow victory to protect in the second leg.
Estudiantes have been in great form throughout the Copa Libertadores this season so will be no pushovers, especially with a more defensive system likely to be on the cards.