The world awaits the return of the Champions League over the next couple of days. Beginning Tuesday, we have mouthwatering ties to look forward to including:

Liverpool v Barcelona
ESPN2, 2:30pm ET

Chelsea v Porto
Setanta Sports, 2:30pm ET

Valencia v Inter Milan
ESPN Deportes, 2:30pm ET

Lyon v Roma
Setanta Sports, 5pm ET

To me, one of the benefits of second leg ties like the ones above is the away-goals rule. It adds a whole new level of suspense to the match. I remember a few years ago watching the Real Madrid against Man United match on TV from Old Trafford — and as the goals went in from both sides, the away goals rule put the match out of United’s reach.

The away goals rule changes the dynamic of a football match. It can create more exciting matches. For example, Liverpool knows that if they score the first goal against Barcelona, they’ll be in an excellent position to proceed to the next round because it means the game would be 3-1 to Liverpool on aggregate. Barcelona’s best bet, meanwhile, is to win 2-0 which would be enough to take them through to the quarter-final stages with an aggregate 3-2 win for the Catalans.