0% Chance, 0% Luck but 100% Faith! Imagine if following happens...
Or could be Umtiti Magic..
I will never rule out Messi magic, if things start and he has one of the better performances...sky is the limit. Quite sure Umtiti magic is not happening though
For me the problem for Barca is not even scoring those 4 goals, it will be much harder to keep their net clean. Only real chance for me is if PSG decides to go super defensive and defend lead from the first game and then after they are 0:2 the panic starts to rise and it gets difficult to start playing. Don't expect them to be that stupid though.
Barca's lineup from recent games, i.e. 3-5-2 looks much more strong defensively. They are able to keep clean sheet in 3 straight games without giving opposition much spaces to attack. However, as temping as this lineup is, they can't go with the same in PSG game. In my opinion, to have any chance of winning the draw, they should go with the following formation:
An attacking 4-2-3-1 formation. Although, I marked Griezmann as CF but we all know how it's in Barca. Messi and him exchanging positions dynamically. The advantage of this formation is that Barca can switch to new working 3-5-2 formation whenever they think they are losing the control. Depending upon which wing is attacking, the lineup can become one of the following:
Important Exclusions/Inclusions:
1. Dest - He has been superb in his new role as the right-midfielder. With Mingueza covering area behind him, he gets more chance and space to dribble forward and doing that superbly. But he hasn't been clinical in shooting. On the other hand, Trincao has been finding net frequently in recent league games. With 4 goal deficit to fill, I bet on Trincao over Dest anyday, even if it makes the squad weaker defensively.
2. Pedri - He has been the talk of this season. He has become such an important player that Koeman had played him in every Laliga and CL games except one. But Busquets is thriving in the new system and surely upper in the pecking order than Pedri. So, Buquets-De Jong in midfield would be best when 4 are playing upfront.
3. Umtiti - This may be one of the worst Laliga season for Clement Lenglet. He alone has cost Barca 4-6 points in the league. But even with his defensive mistakes, he's better than Umtiti any day. Since, Araujo isn't fit, Pique-Lenglet pairing would be ideal with Mingueza-Alba providing further cover.
If Barca fails to increase goal tally with the above formation, Koeman should make early substitutes (in 60-65th minutes) and bring on Braithwaite, Pedri and Dest in the place of Griezmann, Busquets and Mingueza. Depending upon performance, he can even replace Dembele/Trincao with Puig if necessary.
This in my opinion is the only possible plan for the remontada to happen. We can concede a goal or two but this formation is capable of getting 4-5 goals. Let's see what Koeman has in mind.