Eliminating Real Madrid is a dream that might not come true for Arsenal because they are so weak and don't have the experience and confidence to do that. UCL is not EPL that Arsenal is ways winning most of their matches and leading theeague for long without winning the title. That alone has shown that Arsenal is not serious.
If Real Madrid and Arsenal plays 100 matches currently, Real Madrid will win 99 and Arsenal will manage to draw one match. I am not exaggerating because this Arsenal fans are found of over hyping the club who does not have focus and direction.
Such elimination is not realistic, Arsenal doesn't seem like they they have the form and the strength to be able to Eliminate Real Madrid in the champions league because that's the only time they will ever have to meet and play against each other in a league game, I'm not of the opinion that Madrid will be ab to consistently win upto 99 games against Arsenal, that sounds more like exaggeration to me, I know even if it's a very weak team, they will be able to win at least one out of the 99.
Arsenal's strength isn't equal with that of Madrid but at the same time it's not so terrible that they will have to manage to draw just one and loos 99 out of a 100 trail, not with Arteta as their coach. In the history of both teams meeting especially in recent times, the results haven't been so bad that we would say this assumption of yours can be true but in their current form now, for a ten trial game, I believe Arsenal will be able to win at least one even if Madrid is going to win most of it because they have got that strength and form with a very good consistency in their dynamics aswell.
The depth of both squad is another thing to consider to be sure that one can be really too strong enough against the other to the point that they will suffer so much losses if they meet severally, Madrid have a very solid forward and midfield so does Arsenal but the problem for Arsenal will be with their defense which they don't really have such that can be equated to that of Madrid, Madrid seem to have some form of completeness around their team such that it looks like they are not lacking in almost any of the positions.