Duran proved the matchwinner on Saturday, but has spent the summer attempting to find a move away.
Emery said, "It was a very important goal. He’s completely involved with us after coming back from his holidays and after his national team. There will be more rumours about him after his goal, but I believe in him. I gave him 30 minutes today and he’s very important to us."
On whether Duran will stay, he added: "I don’t know."
On fellow goalscorer Amadou Onana, Emery said: "There’s still a lot of adaptation ahead, in training and in matches. Today it was his first official match with us. He was very mature, responsible and intelligent. I think this is the first step we need. The adaptation is going to be long, because there are a lot of things we want to get out of him, but his potential is most important."