spinning-on-backspin

Hi,
 
I tried to implement what I learnt from your video on how to spin on backspin while playing today. One particular problem that I faced was that I couldn’t quite hit through the ball while trying to contact the back of the ball as you have advised in your video. I think that if I hit the back of the ball then I will have to go more upwards rather than through the ball. What do you think?
 
Thanks!