Barcelona and Real Madrid unexpectedly fell by the wayside in the Champions League semi-finals, leaving Atletico and Athletic, similar in name and club colours of red and white, to share the spotlight in UEFA's second-tier competition.
Atletico won the inaugural Europa League, which replaced the UEFA Cup, in 2010 while Athletic, who only field players of Basque origin, are in their first European final since their one and only previous appearance in 1977.
Both sides, coached by Argentines - Atletico by Diego Simeone and Athletic by Marcelo Bielsa - boast strikers capable of lighting up the National stadium in the Romanian capital.
Atletico, who have scored the most goals in this season's competition - 30, will look to Radamel Falcao and Adrian Lopez.
Colombian Falcao set a record in 2010/11 with 17 goals in Porto's triumphant campaign, including the winner against Braga, and is joint top-scorer this season on 10 with Schalke 04's Klass-Jan Huntelaar. Lopez has eight to his name.
Athletic front-man Fernando Llorente is a menace to any defence while in teenager Iker Muniain, the north-coast club have a player destined for a big-money move sooner rather than later.
"Athletic does not depend on one single player, they have some excellent players and throughout the season those players have shown they have stepped up when needed," said Falcao.
"Llorente and Muniain are excellent players but we think of Bilbao as a squad."
