Both teams are not playing top-class football these few weeks. Real Madrid lost their last game against a lowly rated team, Valencia, in Santiago Bernabéu. They have a poor defense that has not shown a lack of quality this period maybe due to aging players. They are just lucky that Despite a lengthy investigation, Kylian Mbappe, Vinicius Jr, Antonio Rudiger and Dani Ceballos were all cleared of wrongdoing due to their celebration after they won the round of sixteen matches. Arsenal is also not in good shape, and it showed as they drew in their last game with Everton. But good that Bukayo Saka will be playing game because without him the Gunners is vulnerable.
Even Real Madrid lost their previous two league games, they play different patterns of game when it comes to Champions league, so do not use their previous league game to conclude, Real Madrid is the king of Champions league and i believe they will win Arsenal home and away as they did to Manchester city.
Real Madrid does not any weaker wings, from the defense to the attacking line are all star players, its Arsenal without striker that will stop Real madrid from advancing to the semi finals, no. The only top game is between Aston villa and Psg.