Balotelli, after being rested for the weekend game against Montpellier, was outstanding for the shock win.
Nice coach Lucien Favre said: "The two goals of Balotelli was very important, psychologically it gave us a lot of confidence.
"Mario was important because he gave depth to the game. Now he has to continue like this, he can grow again. After difficult years, he can return to the top. We will try to help to ensure that he keeps getting stronger.
"Four goals in two games? I dud not expect it!"