Christie came off the bench to score in the 2-0 win.
He later said, "Big win. One thing we are trying to change from last season is to take some points off the top teams. Arsenal are a great side and the red card probably changed the game quiet a lot but nice to beat a title contender.
"We need to take a lot of confidence from this. We were frustrated with the Leicester result before the break, knowing we had a tough run of games coming up but tonight shows we can go and take the game to these teams. We need to into the Villa game next with the same mindset."
On his goal, the midfielder continued: "It was a move off the training ground. I'm not normally the one on the end of it to be fair, but credit to Shaun Cooper who us coming up with loads of different set pieces, he has new ones for us to try each game.
"To do it with all the subs that were coming on as well is brilliant. A great touch around the corner from Justin (Kluivert) and it was great to see it go into the back of the net.
"We didn't set an exact target but we are hoping to improve as a club season in and season out. We were happy with last season but we know we can push further and one of the things that will take us there is to get points off the top six like we have done today."
On the William Saliba red card, Christie said: "To be honest I've not seen it back. All I know is that Eva (Evanilson) is going through on goal and I hardly think that the defender has played the ball so for me I'll stick with the red card."