The Gunners made ten changes from their team that defeated Burnley at the weekend in the Premier League, giving fringe players and youngsters a chance to shine.
Arteta was rewarded for his selection, with Alexandre Lacazette, Emile Smith Rowe, and Eddie Nketiah netting in a comfortable 3-0 success.
Asked if the win was very important, Arteta said: "Really important.
"Confidence rises, competition brings the best out of you when you have difficult moments and the boys have managed to win three games in a row so credit to how they have handled the situation and now they are obviously looking forward to play on Sunday in what is our biggest game of the season.
"As long as we were 1-0 up obviously they were still in the game and in a set-piece situation you can concede a goal. We knew that we had to close the game down and we did it in the end and looked comfortable."
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