Actually, Manchester United will be more enthusiastic when playing at home with a 1-1 capital in their pockets because I believe that Manchester United will improve their performance in order to win at home and ensure that they qualify for the next round.
It's not all about a Ronaldo, but about how to play really well in order to win against Atletico Madrid.
They played aggressively against opponents in Premier League but they did not get good results. From the match in a first leg against Athletico Madrid, I don't see any difference from Manchester United performance. They still rely on De Gea to save their goal, rely on their stars' personal performance and moments to score goals and win or get a draw. It is not what a winning team should have.
Even Athletico Madrid have their problems which are shown with their current position in La Liga, they are still have better connection and psychology in their team. I put my belief on them in the second leg, even it will be hold in Old Trafford.