Jannik Sinner said he does not yet “feel very safe” with the changes he has made to his serve after starting his Australian Open title defence with a shortened first-round win against Hugo Gaston.
The world number two and two-time defending Australian Open champion was in full control of the match at 6-2 6-1 up when Frenchman Gaston abruptly retired.
Sinner led the way on percentage of service games won, external on the ATP Tour during 2025 (92%) but feels there is still “a lot of room to improve”.
Asked about changes he has made since his US Open final loss to Carlos Alcaraz in September, the 24-year-old Italian said: “I felt like the serve was and still is a shot where I need to improve.
“We changed the motion a little bit, the rhythm of the serve. Before, it was a bit too fast in the beginning, now it’s a bit slower.
“At times I still lose it. It’s not a shot I feel very safe with, but we are working on that.
“It is one of, if not the most, important shots we have because it can give you so many great things.”