I can write a book about this, and of course I'm biased here but when they play in Asia, dubious calls usually go in their way, (before today, they scored 3 goals, all of them penalties dubious calls included) since they have money, they think they own everything, when they didn't want to go Thailand, they told AFC to arrange groups and not putting them with the same group as Thailand, now they don't want to play in Iran, they simply call AFC/FIFA and tell them to play in neutral venue. they forced Iraq to play them in Malaysia !! (since Iraq can't host its own matches, they named 2-3 countries to FIFA but Saudis rejected them all to play in wherever they want) and they also play dirty, they are famous for grassrolling and etc.
as for being an Iranian, there are so much hatred between us and Saudis, it's not a "rivalry" like Brazil-Argentina , simply hatred. and the current political tension between two countries makes it even much worse. Saudi Arabia was the only team I wanted to avoid before the draw, only because of this.and there is still a chance to play them in 5th place play-off.