One of my most influential mentors is a very famous legendary Basketball coach called John Wooden he would say to his players –
” When you hurry, you tend to make mistakes. On the other hand, if you can’t execute quickly, you may be too late to accomplish your tasks. It’s a delicate but crucial balance”
I see this all the time on the tennis court, especially with easy put away balls. So, get into position quickly but don’t rush you shot i.e. get you balance, let the ball drop into your hitting zone, then execute with confidence and good racket head speed.
Don’t be move slowly just because the ball is moving slowly. In a sense it is a paradox. Be quick but don’t hurry!