Former No. 1-ranked Angelique Kerber needed to save two match points before fending off Lucie Safarova 6-7 (3), 7-6 (8), 6-2 on Monday to set up a second-round match against Venus Williams. Kerber, coming off a run to the Hopman Cup final in Perth, overcame two rain delays and a tricky second-set tiebreaker to extend her streak to five straight singles wins. Second-seeded Venus Williams had a bye in the first round.
US Open champion Sloane Stephens lost her first match of the year, beaten 6-3, 6-0 by Italian qualifier Camila Giorgi and is short of match practice ahead of the Australian Open which starts in Melbourne next week.
No. 13-ranked Stephens has not won a match since her breakthrough victory over Madison Keys in the U.S. Open final.
The 24-year-old American took a two-month break from tennis after losing her last six matches in 2017 and is now on a seven-match losing streak.
Stephens' exit from Sydney came just one day after French Open champion Jelena Ostapenko was upset 7-6 (3), 6-1 by Ekaterina Makarova on the opening day of the Sydney tournament.
In other first-round matches Monday, former Australian Open finalist Dominika Cibulkova beat No. 8-seeded Anastasija Sevastova 6-3, 6-1 and Australia's Ash Barty posted her first win of the summer in a 6-3, 6-4 victory over qualifier Veronica Cepede Royg.