Penarol begin their quest to win a first continental trophy in 27 years when they face Jorge Wilstermann in the Copa Sudamericana.
The Uruguayan giants are one of the most successful teams in South American football having won the Copa Libertadores five times, although they have not won a continental competition since their last Libertadores success in 1987.
Jorge Fossati's men should be favourites to progress from their two-legged first round tie with Bolivian outfit Wilstermann and will look to put the result beyond doubt with a strong showing in the first leg at Estadio Centenario in Montevideo on Wednesday.
However, despite the odds being stacked against them, Wilstermann boss Julio Cesar Baldivieso is hopeful his side can pull off a shock.
Baldivieso said: "The team is decimated by injuries, but with the calm encouragement, knowing that in football things can go either way and is 11 against 11, we will try to make history."
Penarol, who could face the winner of the tie between UTC Cajamarca of Peru and Colombian side Deportivo Cali at the next stage, are one of four Uruguayan teams competing in the first round of South America's secondary club competition.
Danubio and Rentistas face Paraguayan opposition in Deportivo Capiata and Cerro Porteno, while River Plate take on Chilean club Universidad Catolica, whose Ecuadorian namesakes meet Deportivo Anzoategui in their bid to join the eight Brazilian and six Argentine sides in the second stage.
Only one Ecuadorian team has ever won the Sudamericana, and there will be four sides aiming to replicate the achievement of LDU Quito in 2009.
Last year's league winners Emelec will head the Ecuadorian charge against Aguilas Doradas, and Barcelona meet Alianza Lima.
Meanwhile, Independiente del Valle face Trujillanos, whose domestic rivals Caracas will look to overcome Inti Gas.
Two-time semi-finalists Millonarios begin their campaign to go one better versus Universidad Cesar Vallejo, and their Colombian compatriots Atletico Nacional have been pitted against Deportivo La Guaira.
Elsewhere, Bolivian outfits San Jose and Universitario meet Chilean opponents in Huachipato and Deportes Iquique, General Diaz face Cobresal and Nacional Potosi will aim to end the challenge of Libertad.