Former world number ones Venus Williams and Ana Ivanovic endured a humbling start to the season after the top two seeds were dumped out of the Auckland Classic in the first round by unheralded opponents on Tuesday.
Russian teenager Daria Kasatkina, ranked 75th in the world, claimed arguably the biggest win of her career in taking out the seven-times grand slam singles champion Williams 7-6(4), 3-6, 6-3 in the Australian Open warm-up event.
Williams, 35, made over 70 unforced errors in the scratchy display where she won the title last year to kick off a standout season that saw her claim the WTA's Comeback of the Year award after two other tournament wins in China.
Former French Open champion Ivanovic had little answer to the supreme serving of British qualifier Naomi Broady, who racked up 14 aces in a 7-5, 6-4 win.
The 25-year-old from Manchester maintained her first serve percentage at almost 70 as she took out the second seeded Serb to leave the $250,000 tournament shorn of its headline acts.
Dane Caroline Wozniacki was not at her best on the blue New Zealand hard courts but avoided making it a hat-trick of first round exits by former world number ones as she beat Danka Kovinic of Montenegro 6-4, 6-4.
