“Well, I’m hitting everything I can in terms of the variety of spin, slice, flat, hitting the spots, body, wide, T. I’m trying to mix it up all the time,” Djokovic explained.
“Obviously depends who I play against. Obviously I have different tactic depending on the opponent.
“I feel that my serve this year so far in ATP Cup and also Australian Open has been terrific. It allowed me to win a lot of free points.
“When I’m serving well and getting a high percentage of first serves in, it allows me to feel more comfortable, more confident, kind of step in and play at the higher level of tennis.