Caroline Wozniacki’s first trip to the Brisbane International has ended in a shocking 2-6 6-3 7-6 (7-1) first-round loss to Kazakhstan qualifier Ksenia Pervak.
Wozniacki, who held the year-end No.1 ranking in 2010 and 2011 but is yet to win a major title, had high-profile support from boyfriend and golf No.1 Rory McIlroy in the crowd.
But the 22-year-old struggled with her serve as she surrendered the second set and then had difficulty in the third countering the powerful groundstrokes from the left-handed Pervak.
The 103rd-ranked Pervak was two points from victory, serving for the match at 5-3 and 30-15, but made a series of unforced errors to let the 10th-ranked Wozniacki back into the contest.
Pervak, though, dominated the tiebreaker, winning the first five points.
Earlier, French Open runner-up Sara Errani became the second seeded woman to advance to the second round on Monday.
The world No.6 outclassed Russian qualifier Olga Puchkova 6-1 6-3 to join German fourth seed Angelique Kerber as a first-round victor.
Errani, who upset Australian hope Samantha Stosur in the French Open semi-finals this year to burst into the world’s top 10, next meets Slovakian Daniela Hantuchova.
The fifth-ranked Kerber recovered from a mid-match stumble to eliminate Georgian Anna Tatishvili 6-2 4-6 6-2 in the day’s first match at Pat Rafter Arena.
Kerber next faces Australian wildcard Olivia Rogowska or Puerto Rican qualifier Monica Puig for a place in the quarter-finals.
In other matches, fellow German Sabine Lisicki beat Czech Lucie Safarova 6-2 6-4 to book a clash with world No.1 Victoria Azarenka, who enjoyed a first-round bye.
Frenchwoman Alize Cornet ended the fine summer run of Bojana Bobusic with a 2-6 6-3 6-1 victory over the Australian qualifier.
Bobusic had been on an eight-match winning streak after winning the Australian Open wildcard playoff and then making the Brisbane main draw through qualifying.