I am happy that Atletico Madrid scored early. This will make the match more competitive. Since Madrid won the first leg, Madrid wanted to play defensively in this match and draw the match. Since Real Madrid conceded a goal in the first minute, now Real Madrid will increase their attack speed and try to break Atletico Madrid's defense. We can enjoy an exciting match.
TBH, I'm so surprised that Real Madrid is conceded a goal too early. I also think Real Madrid plans for a more defensive tactic, but it seems they are planning for offensive tactic since the early match. You must realize that Ancelotti put Modric on the starting lineup. If Ancelotti plans for a more defensive tactic, he must prefer Camavinga than Modric.You're right, Real Madrid is trying to play more offensive, unfortunately Atletico Madrid has a better shot attempt. Atletico Madrid uses an effective strategy in this match, it is quite different from the match in first Leg.
We cannot call either Real Madrid or Atletico Madrid weak. Both teams have the ability to qualify for the quarter-finals. Most of the bettors consider Real Madrid as the favorite because Real Madrid is more experienced in the Champions League.
Both Real Madrid and Atletico Madrid are strong teams, it is strange if there is a person who claims one of them is a weak team. 
Sure, both of them have a chance to go to the next round since they have the same aggregate now. But if we consider the history of their matches, Real Madrid is surely more superior. Don't forget, Real Madrid is one of the teams who often win the game through "come back" scheme!