The good thing about two-leg clashes is that the first game does not necessarily decide the eventual outcome. Even when you win 3-0 in the first leg, you can't be sure (ask Barcelona's Twitter admin, he knows):
However, that doesn't mean first leg games don't matter. A confident win makes the remaining task easier for the team that has the advantage. That's why for us bettors it's really important to look at the Champions League quarter-final pairs and see who are the favourites for the first-leg games!
Arsenal vs Bayern
Game date and venue: April 9, The Emirates Stadium
Arsenal: 2.06
Draw: 3.87
Bayern: 3.7
Real Madrid vs Manchester City
Game date and venue: April 9, Santiago Bernabeu
Real Madrid: 2.99
Draw: 3.85
Man City: 2.37
Atletico Madrid vs Borussia Dortmund
Game date and venue: April 10, Civitas Metropolitan Stadium
Atletico: 1.88
Draw: 3.45
Dortmund: 4.47
Paris Saint-Germain vs Barcelona
Game date and venue: April 10, Parc des Princes
PSG: 2.09
Draw: 3.88
Barcelona: 3.60