"At the beginning of my career, I struggled a bit with movement and sliding, et cetera. I think the movement is the biggest one, really, the biggest adaptation that needs to be done on the grass coming from the clay, where players like myself slide quite a lot. On grass, that's not always possible. It is possible to slide, but you can't do it as frequently or as often or maybe as free as you do it on clay," added Djokovic.