Two goals from Wilson Eduardo were enough to give Academica a 2-0 win over Atletico Madrid and end their 16-match unbeaten run in the competition.
Diego Simeone named a relatively inexperienced side for the trip to Portugal, so it was perhaps no surprise to see them struggle in the opening exchanges.
Cleyton had a good effort within the first two minutes for Pedro Emanuel's men, and they were soon a goal up as Wilson Eduardo swept in Joao Dias's cross from the right-hand side to give his side the lead.
After the break, Atleti started to assort their dominance on the game and could have got an equaliser were it not for missed efforts from Raul Garcia and Pedro Martin.
Emre then hit the woodwork for Los Colchoneros, but they just couldn't break down the home side's resolute defence.
And their wastefulness eventually came back to haunt them with 20 minutes remaining. Jorge Pulida fouled Salim Cisse inside the area, and Wilson Eduardo was there to score his second of the night.