Quincy, on loan from Spartak Moscow, was among the goalscorers in the 4-1 win.
"The only thing we could do is bring loan players in who were not under contract," Grant said. "Quincy was one of them. "I knew him from Arsenal and know that he has a lot of quality. I like to develop players and get the best from them and he will be very good if we get potential from him."