There were questions about what the Houston Dynamo could do in the attack. Brad Davis can only do so much out on the left from the run of play. As good as he can cross the ball, he doesn't have blinding pace and there's not a ton of other options in the midfield for the Dynamo to create chances. One place where they are very dangerous though is on set pieces and that has proved true in the first half of this playoff games against the Philadelphia Union.
Houston already has one goal on a set piece and they almost added another, only to see it cleared off the line. Even the set pieces that don't turn into goals though are being won by the Dynamo. They're going up and winning every ball in the air. That is due partly to a very big Houston team, but the Union could bother with marking guys and getting up to challenge occasionally too.
Right now, you'd have to thing Houston gets another goal on a set piece. They're big, they have Davis whipping the ball in and they have a dreadful Union side trying to defend them.