Usually the first games in any European competition are without many goals. It is normal both teams don't risk too much as there is always second leg. This game is not exception at all. But there are two things more.

First reason is that the players from both teams will be little tired. Atletico Madrid played four important games in last two weeks. First they played 0:0 with Valencia in UEFA Lague quarter final (that result was enough for progress) and then they lost three games in row in Primera (against Villarreal, Xerez and Espanyol) . The situation with Liverpool is even worst, as they were forced to travel with bus over 2500 miles from Liverpool to Madrid. So, it is normal the players will not be fresh tonight.

The second reason is both teams will be missing their strikers. Atletico Madrid will be without Sergio Aguero, while Liverpool will be without Fernando Torres. It is clear that their absenceea are very important. So, in situation like this I think Under is the best choice for this game.