Sharapova through as seeds tumble

Sharapova is trying to win her first title since April, 2008

Former world number one Maria Sharapova showed the seeded players the way with a superb win at the Pan Pacific Open as more big names fell by the wayside.

The Russian, unseeded as she makes her way back after injury, thrashed Sam Stosur 6-0 6-1 to reach the last 16.

Earlier, third seed Elena Dementieva went down 6-2 6-7 (3-7) 6-1 to Kateryna Bondarenko in Tokyo.

And there was more bad news for tournament organisers when Caroline Wozniacki retired through illness.

The Danish fourth seed, who finished runner-up at the US Open earlier this month, trailed Aleksandra Wozniak 5-0 when she withdrew.

"I've been sick all week," said the 18-year-old. "Before I left already I was feeling sick and I haven't practiced, and today I felt 'OK, I will try to play.'

There were way too many bad calls from the chair umpire today Elena Dementieva

"I thought I was able to play but as soon as I just got the pulse up a little bit I started to feel ill. There was no chance. I tried my best, it wasn't possible for me today, so I retired. I just try to get better and try to be 100% for Beijing."

Top seeds Dinara Safina and Venus Williams, along with fifth seed Svetlana Kuznetsova, lost on day one and the tournament has been decimated of its leading players.

Others to struggle on Tuesday were sixth seed Vera Zvonareva, who lost 3-6 6-4 6-2 to fellow Russian Alisa Kleybanova, and 13th seed Nadia Petrova, who went down 6-2 6-2 to Magdalena Rybarikova of Slovakia.

But seventh seed Jelena Jankovic came through a tough encounter to beat Sabine Lisicki of Germany 6-3 4-6 6-2.

Eighth seed Victoria Azarenka of Belarus thrashed China's Jie Zheng 6-1 6-1, and 14th seed Marion Bartoli beat fellow Frenchwoman Aravane Rezai 6-4 6-2.

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Olympic champion Dementieva blamed some questionable line calls and fatigue for her loss to a player she had not conceded a set to in four previous meetings.

"There were way too many bad calls from the chair umpire today," she said. "I'm surprised they don't have a challenge system at such a big event."

Dementieva lost in the second round at the US Open, while Ukrainian Bondarenko is currently at a career-high 33 in the rankings after reaching the quarter-finals at Flushing Meadows.

"I played way too many matches in the US Open series," said Dementieva. "I would have liked to have an extra week to get refreshed for this event. I just didn't have the energy."

Sharapova returned to the tour in May after nine months out with a serious shoulder injury and has climbed back up the rankings to her current position of 25th.

However, the Russian has reached just one final in that time and has not won a tournament since Amelia Island in April, 2008.

"I just want to finish the year on a good note," said Sharapova. "I served smart. It was definitely a good day at the office all around."