Arsenal fullback Traore said: "We knew what we were expecting when we went to Braga, but it was still quite shocking really. The referee was really bad and their players were not the best, you have to say.
"Every time you touched them, they just went down on the floor and they would just scream, scream, scream.
"Two seconds later they were up and running like rabbits. Very shocking because you don't see that in the Premier League and when you come to these places you hope for a strong referee. The referee was a bit with them, I think. The referee needed to be honest. That's all he needed to be. In the first half he wasn't honest at all.
"The second half, I think he understood that he had made some mistakes in the first half. He was a little bit better. We didn't shake hands and swap shirts because everyone was really p***ed off.
"We wanted to win to start the group well. I think everyone was frustrated. We need to get a result against AC Milan in our next UEFA Cup match. We are much stronger at home than we are away and I think we can do something against them.
"But if Braga had to come to Fratton Park, it would be a different game and a massive revenge for us. That's all I can say."