MELBOURNE, Australia (AP)
For someone with precious little match ''toughness'' heading into the Australian Open, Maria Sharapova didn't look overly concerned Wednesday.
The second-seeded Russian beat Japan's Misaki Doi 6-0, 6-0 in just 47 minutes, her second consecutive match at Melbourne Park in which her opponent failed to win a game. Doi won only 15 points.
Sharapova, last year's Australian Open runner-up, pulled out of the Brisbane International with a right collarbone injury two weeks ago and had not played a competitive match this year until her 6-0, 6-0 win over fellow Russian Olga Puchkova in the first round Monday.
She is the first woman to post consecutive ''double bagels'' at a Grand Slam since Wendy Turnbull at the Australian Open in 1985.
''I've been playing really aggressive and doing the right things,'' Sharapova said. ''It's not easy to be up so much because you can have a few letdowns. You just have to try to concentrate. My job is to make it as easy as possible.''
Sharapova might find the competition tougher in the next round, where she could meet Venus Williams. The older of Williams sister was scheduled to play her second-round match later Wednesday at Rod Laver Arena, followed by top-seeded and defending champion Novak Djokovic's second-rounder against American Ryan Harrison.
The final match of Wednesday's session on the center court was disappointing, though not wholly unexpected, for the home crowd and Australia's top-ranked woman player.
Ninth-seeded Samantha Stosur, who has spoken of her anxiety over playing in front of her home fans, served twice for the match but double-faulted on match point in a 6-4, 1-6, 7-5 loss to China's Zheng Jie.
''It was a bit of a choke,'' Stosur admitted. ''Obviously it's a hard one to take when you get yourself into a winning position and you lose five games straight.''
Stosur, who had nine double-faults and 56 unforced errors, has never gone beyond the fourth round at her home Grand Slam, lost in the first round last year and also lost in her first matches at warm-up tournaments this year in Brisbane and Sydney.
''I needed to keep fighting and enjoy the match,'' Zheng said. ''It's amazing I came back.''
Earlier, fourth-seeded Agnieszka Radwanksa extended the year's best winning streak to 11 matches. She eased into the third round with a 6-3, 6-3 victory over Romania's Irina-Camelia Begu and remains unbeaten this year, including titles at warm-up tournaments this month at Auckland and Sydney.
''I can play even better,'' said Radwanska, who lost last year's Wimbledon final to Serena Williams. ''I didn't really expect I could win that many matches in a row, and hopefully I can keep going.''
Her last two trips to the Australian Open have ended in quarterfinal losses to the eventual champion - Kim Clijsters in 2011 and Victoria Azarenka last year.
With top-ranked Azarenka and Serena Williams on the other half of the draw, Radwanska's main obstacles to reaching the final are 2011 French Open champion Li Na, who beat Olga Goortsova of Belarus 6-2, 7-5 to reach the third round, and potential semifinal rivals Sharapova or No. 5 Angelique Kerber, who advanced with a 6-3, 6-1 win over Lucie Hradecka.
Williams hurt her ankle in her opening victory on Tuesday, putting her bid for a third consecutive major title in jeopardy. She has only lost one match since her first-round exit at the French Open last year. Williams canceled an outdoor practice session and moved it indoors.
In other women's second-round matches, No. 11 Marion Bartoli beat Serbian qualifier Vesna Dolonc 7-5, 6-0, No. 18 Julia Gorges beat Romina Oprandi 6-3, 6-2, Russian qualifier Valeria Savinykh upset No. 15 Dominika Cibulkova 7-6 (6), 6-4 and Kirsten Flipkens of Belgium beat No. 23 Klara Zakopalova 6-1, 6-0.
American wild-card Madison Keys beat No. 30 Tamira Paszek of Austria 6-2, 6-1.
On the men's side, No. 4-ranked David Ferrer needed five match points before clinching a 6-0, 7-5, 4-6, 6-3 win over American Tim Smyczek, who got into the main draw as a lucky loser from qualifying.
Fifth-seeded Tomas Berdych beat Guillaume Rufin of France 6-2, 6-2, 6-4, and No. 10 Nicolas Almagro and No. 16-ranked Kei Nishikori also moved on. No. 24 Jerzy Janowicz of Poland rallied from two sets down to overpower India's Somdev Devvarman 6-7 (10), 3-6, 6-1, 6-0, 7-5.
No. 20 Sam Querrey advanced when fellow American Brian Baker retired in the second set with a right knee injury and next plays No. 15 Stanislas Wawrinka.
Baker, who returned to the tour last year after missing almost six seasons with a variety of injuries, won a first-set tiebreaker and was level at 1-1 on serve in the second. He was later pushed from Court 6 in a wheelchair.
Tournament organizers said that Baker had a torn meniscus and is expected to be out about four months.
''Yeah, he's the last person that deserves anything like that with his five or six surgeries already,'' Querrey said.