Petkovic packs off out of sorts Sharapova

Schiavone scrapes through to quarters after titanic tussle against Kuznetsova

French Open champion Schiavone took a gruelling four hours and 44 minutes to edge her Russian friend 6-4, 1-6, 16-14 in a Hisense Arena thriller and claim a place in the last eight after the longest women's Grand Slam singles match in the modern era.

Maria Sharapova would happily have played on longer in her fourth round match against Andrea Petkovic but the in-form German sent the former champion and world number one tumbling out of Melbourne Park 6-2, 6-3 in just 79 minutes.

Defending champion Federer took his career record to 10-0 over Spain's Tommy Robredo but his 6-3, 3-6, 6-3, 6-2 victory was not without its problems.  In hot sun on Rod Laver Arena, the 16-times Grand Slam champion raced through the first set in 32 minutes without losing a point on his serve.

Errors started creeping into the 29-year-old's game in the second -- his forehand particularly wayward -- and he conceded an unlikely break to allow Robredo to level the contest.

Federer was in no mood to give Robredo any more encouragement, however, and he upped his aggression level to keep his bid for a fifth Australian Open title on track.  A record five Spaniards had reached the men's fourth round but at Melbourne Park but of the three who played on Sunday, only unseeded Robredo won a set.

Novak Djokovic was in dominant form as he steamed past 14th seed Nicolas Almagro 6-3, 6-4, 6-0 to set up a last eight encounter with Thomas Berdych, who thrashed a third Spaniard, Fernando Verdasco, 6-4, 6-2, 6-3.

Razor sharp Djokovic, the 2008 champion, dominated from the baseline, facing just one break point in the opening two sets then racing through the third in 28 minutes.

Sixth seed Berdych, another of a cluster of players snapping at the heels of the dominant Rafael Nadal and Federer, was also in impressive form in disposing of Verdasco and was talking up his chances of emulating his run to last year's Wimbledon final.

Kuznetsova had promised that she and Schiavone would fight like animals in their fourth-round clash and she was true to her word as they clawed at each other for 284 absorbing minutes.

The 30-year-old Schiavone, the second oldest player to win a maiden Grand Slam, saved six match points in a three-hour final set before calmly pushing a forehand volley to settle the match.

Sharapova has reached just one Grand Slam quarterfinal since she won the last of her three majors here in 2008 and her game once again was lacking as she racked up 30 unforced errors against the dangerous Petkovic who celebrated a first run to the last eight with a cheeky dance.

Wozniacki made a slow start against Latvian prospect Anastasija Sevastova but took command to win 6-3, 6-4 before engaging in more jousting with the media.
Petkovic will meet Li Na in the last eight after the Chinese, a semifinalist here last year, continued her great run of form in 2011 by beating Victoria Azarenka 6-3, 6-3.

Results (fourth round, prefix denotes seeding): Men’s singles: 19-Stanislas Wawrinka (Sui) bt 8-Andy Roddick (US) 6-3, 6-4, 6-4; 2-Roger Federer (Sui) bt Tommy Robredo (Esp) 6-3, 3-6, 6-3, 6-2; 6-Tomas Berdych (Cze) bt 9-Fernando Verdasco (Esp) 6-4, 6-2, 6-3; 3-Novak Djokovic (Srb) bt 14-Nicolas Almagro (Esp) 6-3, 6-4, 6-0.

Women’s singles: 30-Andrea Petkovic (Ger) bt 14-Maria Sharapova (Rus) 6-2, 6-3; 6-Francesca Schiavone (Ita) bt 23-Svetlana Kuznetsova (Rus) 6-4, 1-6, 16-14; 9-Li Na (Chn) bt 8-Victoria Azarenka (Blr) 6-3, 6-3; 1-Caroline Wozniacki (Den) bt Anastasija Sevastova (Lat) 6-3, 6-4.