During his third-round win over Tomas Machac, Djokovic appeared exhausted at times and needed a medical timeout.

He looked fresher against Machac's compatriot, taking control of the opening two sets and stopping Lehecka from earning a break point for more than an hour and 40 minutes.

When Lehecka broke back at the start of the third, an agitated Djokovic shouted towards his team - which includes his former rival Andy Murray - before complaining about noise from the stands while he was trying to serve.

But the seventh seed used the crowd to his advantage in the tie-break, conducting them after hitting a sublime backhand pass and cupping his ear after a deft volley brought up two match points.

"When you are feeling adversity the last couple matches, I think I handled it well," Djokovic told Eurosport.

"Only people who have been there at the highest level understand what you have to deal with. There is a lot on the plate and you have to weather the storm when you are feeling challenged."