By stamina and being energetic, Chelsea has the advantage, but by experience, Fluminense are ahead as they have more experienced players that have tasted different competitions and knows how to face challenges such as the one, they will be facing tonight. The match can swing either direction and will be no surprise to anyone who understand football. It's going to be a very interesting match tonight and the emotion of the supporters of both sides is already high.
I am not sure that Fluminense have more experienced players. I think they are equal in that regard but I still believe Chelsea are the stronger team at the moment. And if you look at the bookmakers odds it shows the same with Chelsea at 1.6 to win and Fluminense at 6. So I would expect to see Chelsea in the final although I doubt they can win this tournament because both PSG and Real look better right now.
Football can be unpredictable no doubt but this particular game the possibility or chances that Chelsea will win and qualify for finals is very high and if we observe, Chelsea has improved recently and they have been doing great in this tournament and Fluminense on the other hand has also been doing well because getting to this stage ( semifinals) is not easy and they really fought a great fight to avail themselves here and as such even though Chelsea will win they will also strive to... I mean try there possible best, I will love to watch the game because I haven't seen Fluminense pattern of play but for them to defeat Al Hilal, it means they are good.