Originally Posted by Greg G
The side view really shows that the stance is too open a lot of the time. Could have a bit more shoulder turn & positive use of the left arm as well.
Yes, the shoulder turn on the forehand. From whatever stance you are in you need to get the shoulders fully turned. The shots you looked best on in the tiebreaker were returning wide serves because it forced you to turn your shoulders. A full shoulder turn should help the falling off to your left, also, since you won't be able to pull off the ball as much.
Make sure you aren't late/contact point is in the right place, since hitting the ball behind your optimal contact point can cause you to pull away from the ball (to get your body out of the way).