Barty's Open rivals hit top gear in Sydney
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.
With Barty opting 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.
Australia's Ajla Tomljanovic suffered a straight sets defeat to world No.9 Paula Badosa of Spain.
World No.45 Tomljanovic hit just one winner in the first set and committed 36 unforced errors for the match on the way to the 6-3 6-4 defeat.
Badosa will now meet either Olympic gold medallist Belinda Bencic or France's Oceane Dodin in the quarter-finals.
Dodin won the first set against Bencic 6-2, but Bencic was up 6-5 in the second set when play was suspended due to rain.
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.