That away goal means Schalke hold the slight upper hand going into the return leg.
But Emery is staying positive, saying: "It's not the best result, but neither is it the worst.
"Schalke have earned a slight advantage for the return game, but we have to be optimistic because we've had good games away from home in the Champions League this season, in fact we haven't lost.
"We have to look for goals as well in Germany and prepare thoroughly for the game so things go better.
"They are a good team. We've suffered against (Klaas-Jan) Huntelaar and Raul. We also had a number of chances, but we're not so upset because anything that isn't a defeat or a goalless draw in the second leg could see us through.
"I'm still convinced about our chances of qualifying."