The main threats to Ash Barty clinching a maiden Australian Open title have all begun to find their groove at the Sydney Tennis Classic.
Barty will be the top seed for the first major of the year which commences on January 17, after the Australian ace began her summer in impressive fashion by winning the Adelaide International last week.
After Barty opted out of playing in Sydney, the world No.1's rivals have been finding their form by advancing to the tournament's quarter-finals. Ons Jabeur downed two-time Wimbledon champion Petra Kvitova 6-4 6-4 to advance to the last eight.
"I've been working a lot on myself and my mentality," Jabeur, who will be seeded ninth at Melbourne Park, said.
"Everybody knows if I decide to do something then I do it and I am going with that mentality from now on."
The Tunisian will meet world No.7 Anett Kontaveit next, with the Estonian showing her class to ease past Romania's Elena-Gabriela Ruse 6-3 6-1.
Spanish world No.3 Garbine Muguruza overcame a second-set fightback from Ekaterina Alexandrova to prevail 6-1 7-6 (7-4) and book her quarter-final spot against 26th-ranked Daria Kasatkina.
The Russian followed up her win over reigning Australian Open champion Sofia Kenin earlier this week by securing a 6-3 6-4 victory over Belgium's Elise Mertens.
Kazakhstan's Elena Rybakina was unable to back up her win over US Open champion Emma Raducanu as the world No.13 was forced to withdraw from her tie with Caroline Garcia due to a thigh strain.
Garcia will face Czech world No.4 Barbora Krejcikova who defeated Jaqueline Adina Cristian of Romania 6-1 7-5. A tie involving Olympic gold medallist Belinda Bencic and France's Oceane Dodin was delayed due to rain when Dodin was a set up.
Australia's Ajla Tomljanovic meets world No.9 Paula Badosa of Spain to round out the day's action.