Lens are going to be a surprising member in the Champions League this season. They have just lost one of their important players as well. Openda has signed for Leipzig. If Leipzig didn't qualify for the Champions League then maybe Lens could have used the Champions League card for their benefit. However they are at equal conditions now so it is a smart choice for him to choose Leipzig.
Because I don't expect Lens to do very impressive things here. They have been quite inexperienced as there has been a very long time period since the last time they joined this tournament.