It's always THE RHYTHM and FOCUS that you need to work on from beginning to highest possible level.
Think, at ATP level, Murray has all the tools as any top pros, but all his losses to the like of Djokovic and Nadal seems to come from the fact that his hitting as it drags out eventually comes out of synch, and seems due to his focus, while Djokovic stays in synch with the ball/hitting/movement; and appear to focus a little longer/better.
Same thing with rec tennis, strokes and hitting at similiar levels are more or less the same. The winner is the one who's more fluid with the movements and is able to focus a bit longer, ie get one more (tough) ball in.