Jannik Sinner survived an early scare in the US Open first round after overcoming Mackenzie McDonald on Tuesday.

The Italian managed a 2-6 6-2 6-1 6-2 victory over the world number 140, having looked well off the pace in the opening set.

McDonald's fellow American Alex Michelsen awaits in the second round for Sinner, who triumphed in his first major match since an independent tribunal cleared any wrongdoing from positive tests for banned substances.

The world number one may have been impacted by those ongoing off the court and was slow to get going, dropping his serve three times en route to a first-set concession.

Sinner held off seven break-point opportunities from the home favourite in that opener, and improved from then on, losing on his serve just once in the second set.

The 23-year-old never looked back from that second-set clincher, easing to victory in just under two-and-a-half hours.

Data Debrief: Super Sinner flying

Sinner, who won his maiden major trophy at the Australian Open in January, is now 49-5 for the season after an impressive 2024.

That run includes lifting a third ATP Masters 1000 crown in Cincinnati last week, where he overcame his next opponent Michelsen in the pair's only ATP Tour meeting to date.