Jan 10 (Reuters) - American Jenson Brooksby has pulled out of the Australian Open after testing positive for COVID-19 ahead of his departure to Melbourne, the 21-year-old said. Brooksby climbed from outside the top 300 at the start of 2021 to a career-high 56 by November following his run to the Newport final and the fourth round at the U.S. Open. The ATP Newcomer of the Year was set to make his Australian Open debut. "Unfortunately I have had to withdraw from the @australianopen. I was scheduled to fly out tomorrow but my coach and I tested positive for COVID this morning," Brooksby said on Instagram. "It isn"t easy to miss a Slam; there are many out there who have suffered worse so I can"t complain. I look forward to making my Aussie Open debut next year. Stay safe." The first Grand Slam of the year begins on Jan. 17.