Utd have won a few titles after hanging about in 8th place or so at the beginning of a season by letting in very few goals and failing to score much themselves while other teams whoop each other 5-0 and end up with nothing in the end.
Winning is great, but not losing is pretty good, too. Maybe this season we'll peak a little later for once, and actually be able to sustain a challenge throughout. You can't do that if you're getting scored against in every game. That's why players like Gervais and Hleb can be very useful. Maybe they don't score, but Helb could keep the ball and Gervais can pin back both an FB and his winger, which makes it all the more difficult to score against us.