The most difficult thing for Real Madrid will be the return leg of this match. If you can't score in a match like this, it will be very difficult for you in the return leg. Real Madrid has a really quality squad. However, Arsenal will have to make a lot of mistakes for this match to turn in their favor. If it is a normal game, Real Madrid may not be able to come back against Arsenal from now on. I am almost sure that Arsenal will advance. There is a 90% chance that Arsenal will advance.
After losing the first leg 3-0, it is very difficult for Real Madrid to win the second leg. However, it is not impossible, because you can have some confidence in Real Madrid's strong squad. They also understand that they will not be able to play normally in the second leg. If they do not do something extraordinary in the second leg, then their exit from the Champions League is certain. But I do not think Arsenal will make a mistake in the second leg and give Real Madrid any chance. If we see a normal match, then Arsenal will have a high chance of winning and maybe we will see Real Madrid go out. Real Madrid's exit depends on Arsenal's plan. The fans will definitely flock to the stadium to see how they can stop Real Madrid.