The Gunners are coming into the cup competition on the back of a disappointing Premier League defeat against Sheffield United on Monday.
Now they face off against Vitoria SC from the Portuguese league at home in the Europa League on Thursday.
Speaking about the game during his press conference, Emery said: "We respect them. They are fourth in the table [in Portugal] and are a very competitive team. They lost the first two games but the games were close.
"Tomorrow we'll expect a difficult match. I think we are showing in Europa League a good performance and a good way in our idea to create and find our way for the future. We are playing compact, aggressively and defensively and offensively very good. We want to extend that tomorrow against Vitoria with respect but also by working to achieve the first position in this group.
"We have the opportunity to first get three points, and we want to get to nine points to be top of the group.
"You ask me how we play better and can improve, this is how we can do it. We want to feel good tomorrow and extend it for Sunday in the Premier League.
"We are feeling good in Emirates Stadium with our supporters. Sometimes we are winning with very good results, like against Nottingham Forest and Standard Liege, but sometimes we are struggling but still winning, like against Bournemouth and Aston Villa.
"Tomorrow we want to extend that good moment with a complete match."