Despite being only 20, Ramsey took well to the task of dictating play in midfield during Tuesday night's 1-0 win and set up Theo Walcott for the Gunners' match winner with a perfect cross in the fourth minute.
That, Sagna claims, shows Arsenal will have little to worry about in midfield this season despite Cesc Fabregas' departure.
"Cesc is a great player. He was one of our best players but that's part of football," Sagna said.
"Every season we start a season and some players leave at the end of it. That's what happens and I just want to wish him good luck. I will miss him of course but Aaron Ramsey did very well and he will show he is a great player as well."