the power source -
it's almost a mirror image of the ww fh.
from the power position (the 1hbh version of padding the dog), the hips open up clockwise. this creates a stretch in the back muscles... the you contract the back muscles, bringing the arm up and across.... during this process you will feel pressure points -
1) on the heel pad because the opening up of the torso is dragging the racket forward
2) on the top 2 sections of the middle and ring fingers because the torso unwind is also pulling the racket up.
this is when you engage the forearm to actively supinate leveraging the above mentioned pressure points.
this is how you get to the finish that looks like Dimitrov.