Fifth seed Ana Ivanovic admitted she was in need of a new approach after crashing out of the Australian Open on the opening day in Melbourne.
Ivanovic looked to be in charge of her match with Czech qualifier Lucie Hradecka on Rod Laver Arena when she took the first set 6-1, but won just five more games in a 6-1 3-6 2-6 defeat.
The former world number one reached the quarter-finals here last year and came into the event on the back of reaching the final of the recent WTA Tour event in Brisbane.
But the 27-year-old Serbian has now failed to reach a single grand slam semi-final in 27 attempts since winning the French Open in 2008.
"I think the whole match I didn't really feel like myself out there," Ivanovic said. "It was really tough for me to find my rhythm.
"There is always nerves in the beginning. I felt like I was maybe lacking a little bit of practice this week, I had some issues. But I played okay in the beginning. I just felt second and third set I really dropped my level.
"It's really disappointing. You know, it's probably the worst thing could happen. But still, the year is young and I really have to now sit and work on a few things and just maybe try to have a different approach to this kind of event and try to see what was lacking."
World number 142 Hradecka could hardly comprehend what she had achieved, adding: "I still don't believe that it's true. Probably in a couple of hours I will know that I am in the second round in Australian Open and I beat Ana. It's two hours after the match and I'm still smiling."
Ivanovic was not the only seed to make an early exit, with 32nd seed Belinda Bencic beaten 6-2 6-1 by Julia Goerges, while 27th seed and former US Open champion Svetlana Kuznetsova also lost in straight sets to France's Caroline Garcia.
Former Wimbledon finalist Sabine Lisicki was another to bow out, the German 28th seed losing in three sets to France's Kristina Mladenovic.
Third seed Simona Halep lost the first two games of her match with Italy's Karin Knapp, but bounced back to win 6-3 6-2.
Ninth seed Angelique Kerber also suffered a surprise defeat, losing a deciding set 6-1 to Romania's Irina-Camelia Begu after winning the previous set 6-0.
Second seed Maria Sharapova and seventh seed Eugenie Bouchard were in action in the evening session against Petra Martic and Anna-Lena Friedsam respectively.
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