Nacional bounced back from their opening-day defeat in the Primeira Liga to record a 1-0 victory over Uniao.
Both sides struggled in the early stages of the game as neither was able to produce the quality needed in the final third to break the deadlock.
The home side took the lead before half time when striker Tiquinho managed to beat Andre Moreira by guiding his effort past the outstretched hand of the keeper.
After the break, Nacional searched for a second goal to kill off the game, but the visitors managed to keep them at bay.
Uniao pushed late on to earn an equaliser, but the home team held out for three points, despite being reduced to 10 men when Ali Ghazal was sent off in the 85th minute for his second bookable offence.