Al Nassr shouldn't lose after getting 2-0 advantage. Al Ittihad won 3-2. They're champions this year because they're the best team in SPL. Karim & Cristiano played together at Real Madrid they must've talked as friends after the match.
I found the game very strange because in the 1st half Al Nassr were dominating the game, they wasted many opportunities, they made very untimely shots, even Ronaldo was making untimely shots, but strangely in the 2nd half Al Nassr disappeared from the game and allowed them to concede goals very easily, almost as if it had been a fixed game, well I could be wrong about my analysis and I'm not accusing anyone.
Sometimes teams end up with bad results like this, and we just have to accept that the yare not doing that great. I understand that it may look like Ronaldo is great, and the team should do great, but the reality is that we are not seeing Ronaldo like he used to be. Neither Benzema really, sure they are seeing Benzema to do a good job, but without others, he is nothing.
The team overall, Ittihad, is better than Nassr, so that is the reason why they are the champions and why they won. If you have a good team, like a "team", instead of bunch of talented players, then you do a better job. Al Nassr may actually have better talented players, like Ronaldo, but Ittihad has a good team that can play better together.