French Open champion Francesca Schiavone set Melbourne Park alight on Sunday night with the longest women's match at a grand slam in the Open era.
The wiry Italian veteran edged Russia's Svetlana Kuznetsova in a four-hour and 44-minute marathon at the Australian Open, 6-4 1-6 16-14, the 30-year-old Schiavone saving six match points before finally capturing the decisive break at 14-14 then wrapping up the three-hour third set.
Schiavone's reward is a quarter-final against top seed Caroline Wozniacki.
Former world number one Maria Sharapova suffered a fourth round shock when she was bundled out 6-2 6-3 by Germany's Andrea Petkovic in an error-strewn performance.
Petkovic faces China's Li Na in the last eight, while the two Swiss men in the tournament will meet with defending champion Roger Federer facing his Beijing Olympics gold medal doubles partner Stanislas Wawrinka.
No.2 seed Federer booked his spot with a four-set win over Spain's Tommy Robredo while 19th-seed Wawrinka beat eighth-seeded American Andy Roddick in three.
Third seed Novak Djokovic beat Nicolas Almagro to book his quarter-final against Czech sixth seed Tomas Berdych, who beat another Spaniard, ninth seed Fernando Verdasco - both wins also in three sets.