Maybe you forgot that there is one more team from the Saudi Pro League that has qualified for the quarter finals yeah it is Al-Ittihad who also won today's match, so there are 3 teams from this league that are still competing in the Asian Champions League. But unfortunately one of Al-Ittihad and Al-Hilal will be eliminated because the two teams will fight each other on March 5. The good side is that it's not Al-Nassr vs Al-Hilal because we hope this match takes place in the final not in the quarter-finals, these two teams are the main candidates to win this tournament I don't see any other team being able to compete with them. Meanwhile, 2 of their competitors came from the Korean League, 1 team from the Japanese League and 1 team from the Chinese league I think none of these teams can beat Al-Nassr or Al-Hilal.
Apart from that, before the AFC semifinal match, The two teams will face each other in the SPL competition first, Which means the two teams will meet twice a week. I think Al Hilal and Al Nassr are one of the favorite teams at the moment, if they don't face each other in the semifinals then Al Ittihad also deserves to be included in the list.
However, it is also possible that Al Ittihad will show a different performance at the AFC event, Who knows they will appear impressive in the future. In the SPL itself, Al Ittihad chances of retaining the championship trophy are no longer possible, the only trophy they might be chasing is the AFC. however, it is clear that Al Hilal is a very difficult team to beat, they have not lost in the AFC and SPL so far.