Russian teen Daria Kasatkina has confirmed she will be one to watch at the Australian Open, tuning up with an impressive straight-sets win over world No.1 Angelique Kerber at the Sydney International.
Kasatkina was far too composed in her second meeting with Kerber, who won grand slams in Melbourne and New York last year to claim top spot on the women's rankings.
The 19-year-old triumphed 7-6 (7-5) 6-2 in 92 minutes, storming into the third round of the Sydney tournament by breaking the top seed's serve on five occasions.
Kerber committed 41 unforced errors, including a loose stroke that resulted in Kasatkina taking the first-set tiebreak. The Russian next faces the winner of Tuesday's match between Australian Daria Gavrilova and Johanna Konta.
Kerber was among a handful of top seeds to fall on Tuesday.
Defending Sydney International champion Svetlana Kuznetsova was ousted by Russian compatriot Anastasia Pavlyuchenkova, while world No.6 Dominika Cibulkova and No.18 Roberta Vinci were also defeated.
After crushing Australian Samantha Stosur on Monday, world No.27 Pavlyuchenkova won her first career meeting with world No.9 Kuznetsova 7-5 6-3.
Pavlyuchenkova will next meet former Wimbledon finalist Eugenie Bouchard, who took advantage of an error-riddled Cibulkova 6-4 6-3 to claim her fourth win in five clashes.
It was also the Canadian star's third win over a top-15 opponent in her past 12 matches, giving her some much-needed confidence ahead of next week's Australian Open.
"Any time you play one of the best players in the world - I think she's ranked five right now - it's like a standard of where you're at," Bouchard said after the match.
"It was okay. I mean, I feel like I could play better tennis. I feel at times we both kind of were making unforced errors, but we were also pressuring each other to make mistakes.
"I have taken a couple of solid steps this week, but I'm far from where I want to be. Even though I won, to me, I could do a lot of things better."
Also on Tuesday, ninth-seeded Italian Vinci had no answers for fellow veteran Barbora Strycova of the Czech Republic, losing 6-2 6-3.
AAP