No. 5 seed Serena Williams reached the quarterfinals of the Yarra Valley Classic with a 6-1, 6-4 defeat of Bulgaria's Tsvetana Pironkova on Wednesday in Melbourne.
Williams never faced any break points while running her record to 6-0 against Pironkova, who fought off three match points before succumbing to the 23-time grand slam winner.
Top seed and World No. 1 Ashleigh Barty of Australia outlasted No. 16 seed Marie Bouzkova of the Czech Republic, 6-0, 4-6, 6-3 to reach the quarterfinals. Barty will face Shelby Rogers, a 7-6 (1), 6-3 winner against No. 7 seed Petra Martic of Croatia.
No. 2 seed Sofia Kenin held off fellow American Jessica Pegula, 5-7, 7-5, 6-2. No. 13 seed Danielle Collins ousted Czech No. 3 seed Karolina Pliskova, 7-6 (5), 7-6 (3). Continuing a bad day for the Czech Republic, No. 4 seed Petra Kvitova was eliminated by Argentina's Nadia Podoroska, 5-7, 6-1, 7-6 (7).
The remaining schedule for all events in Melbourne is in question after a worker at one of the quarantine hotels tested positive for COVID-19.
Top seed Simona Halep of Romania advanced to the Gippsland Trophy quarterfinals with a 6-2, 6-4 victory against No. 16 seed Laura Siegemund of Germany in Melbourne.
Halep will face ninth-seeded Russian Ekaterina Alexandrova, who struck seven aces in a 6-4, 6-2 win over No. 5 seed Iga Swiatek of Poland.
Also advancing were No. 2 seed Naomi Osaka of Japan, No. 3 Elina Svitolina of Ukraine, No. 7 Elise Mertens of Belgium, No. 8 Karolina Muchova of the Czech Republic, Estonia's Kaia Kanepi and Romania's Irina Begu.
No. 7 seed Jennifer Brady breezed to a 6-3, 6-0 win against Russia's Svetlana Kuznetsova in the opening round of the Grampians Trophy event in Melbourne.
Brady won 83 percent of her first-serve points and saved three of four break points against the two-time Grand Slam champion.
Other seeded winners advancing were No. 6 Anett Kontaveit of Estonia and No. 8 Angelique Kerber of Germany. Kontaveit saved five of six break points in a 6-1, 6-3 win against Christina McHale, while Kerber took advantage of 10 double faults by Katerina Siniakova of the Czech Republic in a 6-3, 4-6, 6-3 victory.
--Field Level Media