I don't think you watch Chelsea last match, that made one Chelsea striker to scored two goals for Chelsea to qualified for final. There will be more preparation against this final match because Chelsea is aware how strong Paris Saint Germain players are in this competition, I agree with you that Paris Saint Germain players has proven that they are the strongest team in the UEFA champion League to embraced the title last season because they played perfectly well to defeated inter Milan 4-0 to won the title, but that one doesn't mean Chelsea will lose control in this FIFA club world cup league because they have good players that will make Paris Saint Germain players to fail on Sunday for Chelsea to win the title.
Who do you think will win the final of the FIFA Club World Cup? If we analysis the group stages, Paris Saint-Germain (PSG) topped in the group B with 6 points. Infact the two other teams from that group, Botafogo and Atletico Madrid also ended up on 6 points each. So it was quite a tough group from where PSG qualified.
On the other hand, Chelsea was in Group D and they ended up on 2nd position with six points. Here in this group Flamengo topped the group but they are no longer in the tournament.