The decisive moment came in the first half when Braga were awarded a penalty. Simon Banza stepped up to score.
Erol Bulut made 10 changes at half time with only Jak Alnwick staying on to play 90 mins.
Cardiff City: Alnwick, Romeo (Ng, 45'), Benjamin (McGuinness, 45'), Simpson (Goutas, 45'), Collins (O'Dowda, 45'), Rinomhota (Wintle, 45'), Adams (Ralls, 45'), Tanner (Méïté, 45'), Evans (Grant, 45'), R.Colwill (Robinson 45'), Etete (Ugbo, 45').