Chelsea facing benfica is not going to be an easy task for them if not for any reason but because Jose mourinho will be trying to prove a point. Benfica coach Bruno lage was sacked few days ago after a terrible defeat by qarabag and won't be willing to accommodate another lost in their next game against Chelsea in the coming days and secondly the presence of a new coach requires an excellent performance just to protect his new job at the club. Apart from providing protection to his job, the new coach Jose mourinho is a high profile coach with a lot of achievement in his coaching career, so finding the best way to win won't be a difficult one for him.
Benfica should be able to understand Jose Mourinho if in the end they were defeated by Chelsea because after all he had just been appointed as a coach and certainly needed time to manage the team to be better and directly facing Chelsea was of course a very tough challenge for Jose Mourinho even though Chelsea was his former club but Chelsea's performance had improved so Jose Mourinho no longer recognized the strategy used by Chelsea currently.
I don’t think Benfica will be able to win the game, no matter what, because Chelsea hardly lose games against Benfica. Even though, for now, we can consider Jose Mourinho as a big threat to them, Chelsea has not changed that much, so he might break their strategy and end the game in a draw. But still, I have higher hope that Chelsea will definitely end up winning the game, because it will be easy for them. As they lost their first game in the Champions League, they won’t like to miss this opportunity.