Novak Djokovic is not having a good day on serve and it is costing him. Jannik Sinner brings up a double break to lead 5-1 in this opening set.

Djokovic is struggling when he makes first serves, only landing about 43 per cent of them and winning only half (44 per cent) of those points.

He also has 15 unforced errors compared to Sinner’s four and two double faults.

“Sinner seems to know what Djokovic is doing before he has even done it. That has been partly the story of this opening set,” Sam Smith says in commentary for Nine.

“The start is almost too good from Jannik.”