The England star said: "They've played extremely well and played some good football, but I still think that we're the top team in England. It'll be a fabulous game for the fans to enjoy but we'll be very confident going into the game.
"We've got some time to focus and look at some tape of Arsenal and look at what they do well. We look good, our offensive play is very good. But we have some things we can work on, even going forward. We had some wonderful moments against Boro but at times we were a bit complacent.
"We could have scored more goals so we have some things we can work on - and that's a great thing. We're winning comfortably and we're not even hitting top gear yet."
Hargreaves made his return against Boro after struggling this season with various knee problems.
But the midfielder, who signed from Bayern Munich for £17million this summer, is hoping his injury problems are now behind him.
Hargreaves added: "I felt a bit stiff and sore afterwards but that happens with injuries like this. It has been a frustrating time, very stop and start. I have spoken to a lot of doctors and specialists who have explained it is not really a problem with the knee, it is more a structural problem. I have been trying to play through it but it has been difficult at times.
"Now I am fit, I just want to try to remain that way for the rest of the season."