The Gunners have drawn criticism from a large section of their supporters this summer for so far failing to make any major signings during the current transfer window.
However, the Frenchman is adamant that Arsenal have a chance of winning in every competition they are in over the next year.
"Everyone is confident. Of course the first game [against Aston Villa] was not great - we lost at home and dropped points. But we knew we had a good team. We kept working hard and kept our heads up and have managed to win games," Sagna told talkSPORT.
"We have very good players. We have a young team and want to improve but we can beat anyone. We played a very good team in Fenerbahce with experience and we managed to win - even away it was not easy. If we stay focused I believe we have a very good team which is competitive."
French striker Yaya Sanogo is the only Arsenal signing so far this summer.