Berrettini was racing to be fit after struggling through his Thursday exhibition match at the Kooyong Tennis Club against Australian Tristan Schoolkate, displaying signs of discomfort as he lost 7-5, 6-3.
He then withdrew from a Melbourne Park opening week practice game against young Norwegian Nicolai Budkov Kjaer with what was an undisclosed illness and was racing to be fit for his Monday afternoon encounter with Alex De Minaur on Rod Laver Arena.
The former Wimbledon finalist, who is no stranger to producing early round shocks at Melbourne Park, having eliminated Rafael Nadal from the second round of the 2023 edition, announced his departure on Monday.
“I’m really sorry to have to withdraw from the tournament,” Berrettini said on Saturday evening local time.
“I have always enjoyed being and playing here and feeling your incredible support. Thank you to the tournament for their fantastic organisation, and I hope to see all of you again very soon.”
Rank no. 113 American Mackenzie McDonald has been chosen as the lucky loser and will be making his seventh main draw appearance in eight years at the Australian Open, having lost his final qualifier to Canada's Liam Draxl on Thursday.
McDonald's best Australian Open run came in 2021, when he lost to eventual runner-up Daniil Medvedev in the fourth round.
De Minaur has defeated McDonald in all three previous meetings, with the most recent coming in February 2022.
