I personally do not think that Fenerbahce has a chance of qualifying for the next round. Rangers defense is strong. Since Rangers are ahead by 2 goals in the first leg, Rangers' main target in the second leg will be not to concede a goal. If Rangers play defensively, it will not be possible for Fenerbahce players to win by a big margin of 3 goals.
Fenerbahce doesn't have a chance to win this game unless there will be red cards or turning events in Rangers side. They missed badly their chances to pass and definitely their opponent will play defensively more than usual..
I think Fenerbahce might manage to get a draw or win with a goal difference at best but definitely it will be very unlikely to see them passing this stage.
Looking at Rangers' match strategy and style of play, I don't think Rangers will lose by a big margin against Fenerbahce. Rangers are a very tactical team. We saw in the first leg that their main target was to keep their defense strong. And even then, they tried to score goals from counterattacks. I wouldn't be surprised if Rangers played a completely defensive strategy in the second leg. It's more likely.
Even if Fenerbahce had lost by 2-1 or 1-0, I still think Fenerbahce would have a chance of qualifying for the next round. But Rangers' defense is strong. It won't be possible for Fenerbahce to win by a big margin of 3 goals against this team.