Maria Sharapova, a five-time Grand Slam champion, has not played since pulling out of a tournament in her native Russia at the end of January.
Umpire Alison Hughes was lucky to escape injury as the spider-cam ripped the sun shield right off her chair.
Australian Open 2019: Ashleigh Barty stunned five-time Grand Slam winner Maria Sharapova in a three-set thriller.
Maria Sharapova won 6-4, 4-6, 6-3 with the roof closed on Rod Laver Arena.
The pressure on the reigning French Open champion will only increase in her next round.
The Russian five-time Grand Slam champion was forced to stay up late in her second-round match.
The 31-year-old has only conceded three games en route to round three at Melbourne Park, where she won the title in 2008.
Rafael Nadal is bidding to become the first man in the Open era, and only third in history along with Roy Emerson and Rod Laver, to win each Grand Slam on two or more occasions.
Serena Williams won her 23rd title and seventh at Melbourne Park while eight weeks pregnant two years ago.
Simona Halep takes the top seeding among the women courtesy of her world number one ranking.
Maria Sharapova, ranked world number 29, decided to throw in the towel in the second set.
Wang Xinyu had to retire hurt, apparently after feeling pain in her thigh, while she was leading 5-2 in the second set.
The match between Maria Sharapova and Timea Bacsinszky lasted an hour 42 minutes.
Maria Sharapova laughed off suggestions that losing in the US Open fourth round represented the toughest period of her life.
Maria Sharapova was knocked out of the US Open in the fourth round on Monday, losing 6-4, 6-3 to Spanish birthday girl Carla Suarez Navarro.
Schnyder, the oldest ever player to make the main draw of a Grand Slam via qualifying, was outgunned by the five-time major champion in the first set and for the majority of the second.
Sharapova needed just 66 minutes to see off 12th-seeded Kasatkina in an impressive and timely display of big-hitting with the US Open getting underway in just under three weeks' time.
Two-time Cincinnati champion Serena lost the Wimbledon final to Angelique Kerber last month.