I agree, Al Hilal were fortunate to beat Manchester City, although they were surprisingly defeated by Fluminense. Chelsea success in winning the Club World Cup was the culmination of all the surprises, defeating PSG, the much fancied Champions League holders. Admittedly, football is full of surprises, there's no guarantee that the favored team will finish the match as predicted.
It wasn't just luck, as Manchester City were experiencing a decline in form at the same time. Al Hilal capitalized on the opportunity to defeat Manchester City. After defeating Manchester City, Al Hilal was considered the favorite, but they were defeated by Fluminense. It's safe to say that Al Hilal's performance wasn't strong enough to compete in the CWC.
In the Saudi Arabian League, I have no doubt that Al Hilal remains the favorite to win the SPL title, but in European competition, SPL clubs are still far behind.