Australian Open: Andrea Petkovic beats Maria Sharapova
Australian Open, Melbourne Venue: Melbourne Park Dates: 17-30 January Coverage: Watch on BBC TV, Red Button, BBC Sport website (UK only) & Eurosport; listen on BBC 5 live sports extra and online; text commentary online;
Slack Sharapova stunned by Petkovic
Former champion Maria Sharapova has exited the Australian Open after suffering a straight-sets defeat by number 30 seed Andrea Petkovic.
The German was rarely troubled in beating the 2008 Australian Open champion 6-2 6-3 on Sunday and will now play Li Na in the quarter-finals.
Top seed Caroline Wozniacki overcame a sluggish start to defeat Anastasija Sevastova 6-3 6-4.
Wozniacki will now play Francesca Schiavone who beat Svetlana Kuznetsova.
Sharapova has struggled since she returned to the tour in 2008 following shoulder surgery and looked a shadow of the player who won three Grand Slam titles.
The Russian was disappointing against Petkovic, serving five double faults and making 30 unforced errors to her opponent's nine.
For Petkovic it was the first time she has reached a Grand Slam quarter-final and made up for her first outing at Melbourne Park when in 2008, the same year Sharapova won the title, she injured her knee in the first round against Anna Chakvetadze and was out injured for eight months.
Sevastova makes it tough to get any rhythm but I pulled through
"Maria is such a great champion, it's just two or three points and she comes back, and she started playing so well in the last couple of games, so I was a little nervous," said Petkovic.
"But I am happy I closed it out in the end."
Wozniacki, eyeing her first Grand Slam, was blown away by the 46th seed Latvian to trail 3-1 but five successive games handed the 20-year-old the opening set.
Sevastova showed glimpses of a recovery with an early break, but the Dane edged through despite the continuing errors.
Wozniacki and Sevastova were the two youngest women left in the draw and the battle began in intriguing fashion with the 20-year-old Latvian, who had never previously got beyond round two in a Grand Slam, dominating the number one seed.
Wozniacki has been far from her best this week in Melbourne and a shock defeat looked on the cards in the first 20 minutes as she lost her opening serve and then found herself 3-1 behind.
The wobbles continued when she was serving at 30-30 in the fifth game but the 2009 US Open runner-up seemed to be inspired by her struggles and finally took the game thanks to two blistering backhands.
With Rod Laver Arena bathed in scorching sun, Sevastova, whose tournament preparations were hampered by bronchitis, looked to be suffering with the conditions and as her unforced error count reached 19, her opponent pounced to take the first set.
Breaking to love at the start of the second set secured Wozniacki's sixth game in a row, but then the mistakes returned as both exchanged breaks of serve.
Wozniacki looked to be cruising at 4-2 but Sevastova finally showed some of her earlier form and levelled at 4-4.
Fans of the blonde Dane were finally given some relief as their player steadied the ship to break in the ninth game before stumbling through her service game to secure a hard-earned, if a little shaky, victory.
"Sevastova is a tough opponent and she mixes the game up well," said Wozniacki.
"She makes it tough to get any rhythm but I pulled though and I'm very pleased to make the quarters."
Elsewhere, China's ninth seed Li eased past Victoria Azarenka in straight sets.
Li, who lost to Serena Williams in last year's Melbourne semi-finals, was too strong throughout the 88-minute battle as she dumped out Belarus star Azarenka, ranked eighth with a scoreline 6-3 6-3.
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