ADELAIDE, Australia (AP) -- World No.2-ranked Aryna Sabalenka has lost another first-round match at an Australian Open tune-up tournament to a much lower-ranked opponent.
Sabalenka lost 5-7, 6-1, 7-5 to Sweden's Rebecca Peterson, who came into the match at the Adelaide International ranked No. 395.
Last week in the opening round of the first Adelaide International tournament, Sabalenka lost 7-6 (6), 6-1 to Kaja Juvan, who is ranked 100th.
While top-ranked Ash Barty is a perfect seven from seven this year after sweeping to the singles and doubles titles at the first of successive Adelaide Internationals, Sabalenka hasn't won in more than two months. Barty is not playing in Adelaide after her successful last week in the South Australian state capital.
At the Sydney Tennis Classic, Ajla Tomljanovic beat Anna Schmiedlova 6-2, 6-3 in a first-round match.
Tomljanovic will next face fifth-seeded Paula Badosa after the Spanish world No. 9 beat Jelena Ostapenko 7-6 (1) 6-1.
The 28-year-old Tomljanovic has never gone further than round two at the Australian Open but last year made the quarterfinals at Wimbledon in a career-best showing.
Two high-profile British players were scheduled to play their first-round matches later Tuesday -- Andy Murray in Adelaide and U.S. Open champion Emma Raducanu in Sydney.