Paraguayan giants Cerro Porteno recorded a narrow 1-0 triumph over Argentinian side Tigre in the first leg of their Copa Sudamericana semi-final.
Argentinian striker Roberto Nanni netted the only goal of the game just a minute into the match in Asuncion, taking advantage of a mistake by visiting goalkeeper Javier Garcia.
Cerro Porteno boss Jorge Fossatti said afterwards: "Yes, we only have a one-goal lead, but we have already showed that we know how to play as visitors. Another important fact is that we didn't concede a goal here, we did good work in defence."
Both teams will clash again next Thursday night in Victoria, in the northern suburbs of Buenos Aires.
Meanwhile, in Avellaneda, Argentinian giants Independiente could only manage a 2-2 draw at home against Chile's Universidad Catolica.
Enzo Andia headed the visitors into a third minute lead from Tomas Costa's free-kick but fellow defender Cristian Tula equalised just before half-time.
Substitute Lucas Villafanez put Independiente ahead in the 54th minute with a powerful shot from the edge of the area, only for Nicolas Castillo to level the scores 16 minutes later.
The second leg also takes place next Thursday, at the Estadio San Carlos de Apoquindo in Santiago.