39 sounds normal to me as your average quality is 2 stars higher and it's your home ground.

If the quality is more or less the same you may lost 1-4 or something, possession isn't as important as you may think.

The real factor to see if your formation counters the enemy formation, is the chance creation ratio, given by
Shots+Corners+Freekicks+EnemyTackle : EnemyShots+EnemyCorners+EnemyFreekicks+Tackle

For hard counters you can out-gun your opponent by more than 2:1 which greatly improves your chance of winning.