Of course, football is full of surprises. My biggest shock will be for Arsenal to win Madrid, because I have never expected that to happen even in my dreams. Arsenal is strong and are in form but it will be very difficult for them to go beyond the quarter finals, because of the opponent that they will face. We know how Madrid do take their UCL matches very serious than every other competition.
Let's see the first leg match later where Arsenal will play at home. If Arsenal can get an advantage in the first leg, maybe it will reduce their burden a little in the second leg when playing at Madrid's home.
Both teams are strong teams that unfortunately met in the quarter-finals. Madrid who in the previous round also had a little difficulty facing Atletico, this time facing Arsenal must reduce mistakes. Madrid may be more favored to advance to the next round, but let's see how the match will go.