Maria sharapova
'I'm saying goodbye': Maria Sharapova retires from tennis
In 2016, the Russian admitted she had failed a drug test in Australia due to the detection of meldonium.
Australia's Nick Kyrgios also cantered into the second round, but fourth seed Daniil Medvedev had to fight his way past American Frances Tiafoe in four sets.
The 32-year-old former world number one carried a haunted look at times in a 3-6, 4-6 defeat to Croatia's 19th-seeded Donna Vekic.
The 32-year-old, who won the tournament in 2008, has slipped down the rankings to 147, outside automatic qualification, and was bounced out of the Brisbane International this week in the first round.
The five-time major winner will open her 2020 campaign in Brisbane after being awarded a wildcard by organisers in preparation for the Australian Open later in January.
Haji Mohamed Dawjee says you cannot compete for superiority when you are not on the same level.
Sharapova, competing for the first time since retiring from her first-round match at Wimbledon, appeared to be on course for just a fourth match win since January when she went up a set and an early break on the 16th seed from Estonia.
The five-time Grand Slam champion has not played since the end of January after taking time out to recover from a shoulder injury but edged a tight opening set against Kuzmova before strolling through the second.
Sharapova, 32, a five-time Grand Slam champion, has not played since pulling out of a tournament in her native Russia at the end of January.
The 31-year-old has been struggling back to elite fitness since watching from the sidelines during her 15-month doping ban that ended in 2017.
It was curtains for South African Kevin Anderson, who slumped out to young American Frances Tiafoe and became the highest seed, at five, to be sent packing so far.
Defending champion Caroline Wozniacki, seeded third, took just over an hour to secure her second consecutive straight-sets win.
The 17-time Grand Slam champion, who cut short his 2018 season to have surgery on a foot injury, cruised through to round two of the opening major of the year 6-4, 6-3, 7-5 against Australian wildcard James Duckworth.
Sharapova struggled to move on court and conceded the opening set 6-1, with coach Thomas Hogstedt urging the Russian to take her game to the next level or call for a medical timeout.
Sharapova is now undefeated in 22-night matches at the Billie Jean King National Tennis Center.
The Romanian sent a forehand into the net to offer Sharapova a break point, and allowed the Russian to level at 4-4 with a double fault.
Patty Schnyder was outgunned by the five-time major champion in the first set and for the majority of the second.
Serena Williams says had suffered a pectoral muscle injury in her third-round victory against Germany’s Julia Goerges.
Maria Sharapova is seeking redemption after a 15-month doping ban with a third French Open title.