Jannik Sinner says he "still has room to improve" in his Australian Open title defence after beating Marcos Giron to reach the fourth round.

World number one Sinner was not at his fluent best but stepped up when needed to beat the American 6-3 6-4 6-2.

The Italian won his first major at Melbourne Park at the start of a remarkable 2024 that saw him win the US Open, six ATP Tour titles and finish as year-end number one.

He hit 35 winners and eight aces against Giron, but also made 37 unforced errors.

"Every match has its own difficulties. I still have room to improve, but every win is great," said 23-year-old Sinner.

"If I want to go on in this tournament I have to improve."

Sinner is on a 17-match winning streak, with his last defeat coming in the Beijing Open final against Carlos Alcaraz in October.

Spain's four-time major champion Alcaraz is on the opposite side of the draw in Melbourne Park, meaning he and Sinner could only meet in the final.

Alcaraz plays Britain's Jack Draper in the fourth round on Sunday, while Sinner will face either Miomir Kecmanovic of Serbia or Danish 13th seed Holger Rune.