I hit that shot. There is a lot that goes into it, and the wrist is probably the last element. You want to be turned to the side and prepped before the ball bounces. Get your weight shifting from your right to left foot on your stroke and use your offhand and hips to swing the racquet. That will take the wrist out of the equation.
Another thing i do to set my wrist is when i turn to prep the racquet, i make sure the tip is pointed up to the sky before i let go of the stick. I do this while stalking the ball and turning.
Other thing that helps is using an 18x20 pattern. It is not a must but it does lower the trajectory of the ball and allows you to really drive it deep with spin like you are describing.