This is very important competition and one goal will mean lot, and conversely one goal conceded will be very detrimental thing so that when one team gets the advantage in game they will be more careful and focus on defense with the aim of minimizing the occurrence of draw.
In almost every important competition, the same thing will always happen, especially if it is deciding round such as the quarter-finals or semifinals where it is clear that the losing team will be eliminated from the competition.
A game like this will definitely be present between Bayern Munich vs Real Madrid and we could see it yesterday in their match actually happening, Real Madrid after gaining the lead tended to optimize their defense more.
But in the end what happened was draw, this would be much more profitable than losing and having to suffer from being left behind on aggregate in the first leg match.
For the second leg match, I sure that Real Madrid will be far superior and of course Real Madrid will also have the first goal in the match, but the game in the second leg will seem much different from yesterday.
Bayern Munich is not team like Manchester City and to be able to hold draw or win in an away game is absolutely impossible for Bayern Munich.
The first leg of the UCL semi finals phase has been concluded and on Tuesday, there were lots of goals flying around as neither of the teams resolved to get overpowered. The first fixture was played in Germany and again Real Madrid did well to secure an away goal advantage for themselves, whilst working towards ensuring that there's good goal margin when Munich goes to Spain for the second leg.
Yesterday, Dortmund did well to hold PSG down to a 1-0 victory, not giving the room for an away goal advantage and also maybe giving themselves a bit of hope as to how to approach the second leg. PSG did their best in the game but maybe the home advantage worked for Dortmund, although the margin wasn't wide but at least twas a win. The struggle is still on. At this moment, both fixtures for the second leg would be heated up as the teams would be eager to play extra to make sure they secure qualification.
Real Madrid I believe will do their best in Spain considering their game records this season and also their quest for the trophy. They have a goal advantage already, they only need to seal it and they'll do so well when they're able to keep a clean sheet in the second leg. PSG would host Dortmund and I personally believe the atmosphere would be different and they'd give Dortmund the game of the season in a few days. Both teams will try to maintain their stand but as always, the better team would scale through.