Petra Kvitova followed Simona Halep and Venus Williams in making an early exit from the Australian Open as Daria Gavrilova enhanced her growing reputation on Margaret Court Arena.
Russian-born Australian Gavrilova has developed a welcome knack of taking down opponents ranked inside the top 10 and thrilled the Melbourne Park faithful with a 6-4 6-4 victory over the sixth seed, whose performance was riddled with unforced errors.
Top seed Serena Williams had no such problems, recording a 6-1 6-2 success against Hsieh Su-wei, while there were also wins in straight sets for fellow big names Maria Sharapova and Agnieszka Radwanska - the latter coming through a potentially tricky clash with Eugenie Bouchard.
Williams, the defending champion, could hardly have asked for a more satisfying day's work as she cruised into round three, while Radwanska recovered impressively after falling 4-2 down to Bouchard early on.
The 2008 winner Sharapova was virtually untroubled as Aliaksandra Sasnovich won just three games on Rod Laver Arena.
And although Kvitova flopped, Carla Suarez Navarro, Belinda Bencic and Roberta Vinci all avoided upsets.
SEEDS SAYING GOODBYE
Kvitova was Wednesday's high-profile casualty, but Svetlana Kuznetsova - the 23rd seed - also bowed out courtesy of a straight-sets loss to Kateryna Bondarenko.
Kristyna Pliskova was knocked out of the women's singles by Monica Puig, but not before setting a new record for the most aces in a WTA match, with a stunning tally of 31.
A trio of teenagers remain in the top half of the draw, with Bencic joined in round three by Elizaveta Kulichkova and Daria Kasatkina. However, the latter faces Serena next up.
SOCIAL MEDIA SWEEP
"Come onnnnnn!!!!" - Gavrilova celebrates her victory over Kvitova with a succinct Twitter post, accompanied by a love heart emoji and, of course, the obligatory selfie.
Gavrilova also received support from Nick Kyrgios, who she teamed up with to secure Hopman Cup success this month. Kyrgios tweeted: "Massive from you tonight @Daria_gav keep it going. #NoLimits."
After seeing off the threat of Bouchard, Radwanska tweeted: "Tough opponent tonight and some fun rallies. Pleased to get the win."
THEY SAID WHAT?
Kasatkina beat Venus Williams in Auckland this year, so Serena will not be taking anything for granted. "I don't think it's going to be be easy," said the world number one. "Any time someone is beating Venus they are more than likely playing really good."
Gavrilova enjoyed herself on Margaret Court Arena. The 21-year-old said: "I love the crowd. I love people watching me. It helps me a lot."
"I think in a couple of months we going to see her more deeper in the grand slams," Radwanska tips Bouchard to make a big impression later this year.
Gavrilova will face Kristina Mladenovic in the third round, while Monica Puig and Lauren Davis are the respective next opponents for Radwanska and Sharapova.
The likes of Victoria Azarenka, Garbine Muguruza and Angelique Kerber are in second-round action on Thursday - and will be eager to avoid a similar fate to Kvitova.
Serena Williams (1) beat Hsieh Su-wei 6-1 6-2
Agnieszka Radwanska (4) beat Eugenie Bouchard 6-4 6-2
Maria Sharapova (5) beat Aliaksandra Sasnovich 6-2 6-1
Daria Gavrilova beat Petra Kvitova (6) 6-4 6-4
Carla Suarez Navarro (10) beat Maria Sakkari 6-7 (5-7) 6-2 6-2
Belinda Bencic (12) beat Timea Babos 6-3 6-3
Roberta Vinci (13) beat Irina Falconi 6-2 6-3
Kateryna Bondarenko beat Svetlana Kuznetsova (23) 6-1 7-5
Kristina Mladenovic (28) beat Nicole Gibbs 6-1 7-6 (7-4)
Monica Puig beat Kristyna Pliskova 4-6 7-6 (8-6) 9-7
Lauren Davis beat Magdalena Rybarikova 7-6 (9-7) retired
Anna-Lena Friedsam beat Wang Qiang 6-3 6-4
Yulia Putintseva beat Han Xinyun 6-3 6-1
Elizaveta Kulichkova beat Monica Niculescu 6-4 2-6 6-4
Daria Kasatkina beat Ana Konjuh 6-4 6-3
Margarita Gasparyan beat Kurumi Nara 6-4 6-4