The Portuguese side lost 1-0 in their away leg on Thursday night and were largely stopped from playing their natural game by the Turkish side.
Aimar, however, is confident that will not be an issue in the return leg.
"It was quite a difficult game for us tonight, but I have to say the atmosphere in the stadium was absolutely amazing," UEFA.com quotes Aimar as saying.
"We had a tough night, as we couldn't really play the sort of game the coach expected us to play, but I believe we can still turn things around in the return game. It isn't over yet."
Egemen Korkmaz's goal was enough for Fenerbahce to win on the night.