Czech teenager Linda Noskova has started the year with a bang, upsetting world No.8 Daria Kasatkina in the first round of the Adelaide International on Monday.
The 18-year-old qualifier claimed her first top-10 victim with a 6-3 6-7 (2-7) 6-3 win over the Russian third seed.
Australia's Jaimee Fourlis suffered a heart-breaking loss to Ukrainian Marta Kostyuk, going down 6-1 3-6 6-4.
Noskova, ranked 102 and playing in just her fifth WTA main draw, had to do it the hard way after failing to serve out the match in the second set when up 6-5.
She had already accounted for world No. 58 Anna Kalinskaya and No. 43 Anastasia Potapova during qualifying before banking the rousing win over the third seed.
Noskova now will face the winner of Tuesday's match between Australia's Priscilla Hon and American qualifier Claire Liu.
Another Russian, fourth-seeded Veronika Kudermetova, had no trouble in her opening match, easily accounting for young American Amanda Anisimova, 6-3 6-0.
In other results, Irina-Camelia Begu of Romania overpowered another American Shelby Rogers 3-6 7-6 (7-5) 6-1.