I doubt if they can come back and qualify for semifinals, if it was 1 or 2 goals I would have said it is 70% possible to come back and qualify and again this currently Real Madrid performance is not longer encouraging and like I said earlier the coach will be confused right now, they are playing against Alaves today, I don't know if the coach will prioritize the champions league or La Liga because the point difference between Real Madrid and Barcelona is 7 now that is if Real Madrid didn't win today but if I'm Ancelote I will make sure to win today's match because it seems they are already out in the champions league.
With three goals conceded it might be a little more difficult to turn things around because Arsenal themselves will not try to defend in order to maintain their chances of qualifying for the next round. But what Arteta needs to be aware of is how Real Madrid's quick goal occurs because if that is achieved then the tension of the game will definitely change where Arsenal will feel much heavier pressure.
Real Madrid has the ability to put opponents under pressure, especially since we know that the Santiago Bernabeu is a home ground that is quite difficult to conquer. Arteta needs to think of a special strategy so that Real Madrid does not do something that could cause Arsenal's chances of failing to advance to the next round.