Many fans expected the young forward to be sold in the summer, with Chelsea and West Ham circling at one stage of the window.
However, Duran remained at Villa Park and has been on fire since the season started.
After Duran's goal in victory over Leicester, Emery told reporters: "Always we speak about his potential and the most important (thing) is that he focuses and he has consistency with us.
“When he arrived in pre-season, he was focusing to stay with us. He has trained well and he has started playing against West Ham, last week and today. He is having chances and scoring.
"Even when Watkins is not scoring, he is doing good work. He had two very good chances last week and today he had two very good chances. The goalkeeper saved them last week and now. We have to try and get the best performances individually and collectively."