The seeds continue to crash out at the Brisbane Tennis International, with fourth-seeded Slovak Dominika Cibulkova the latest big name to fall after succumbing 7-5 6-2 to American teenager Madison Keys in the first round.
The 2014 Australian Open runner-up became the third women's seed to fall following upset losses for German Andrea Petkovic (fifth) and former world No.1 Jelena Jankovic (sixth) on Sunday's opening day.
World No.11 Cibulkova, 25, had no answer for the 19-year-old Keys, who wrapped up the first round clash in 90 minutes.
The only respite for the Slovak came in the second set when play was momentarily suspended at 2-2 due to slippery conditions caused by rain blown into the largely covered arena.
Keys booked a second-round clash on her Brisbane debut with compatriot Varvaro Lepchenko, who came back from 5-1 down in the third set to upset world No.22 Sam Stosur on Sunday.
World No.30 Keys is coached by five-time grand slam champion Lindsay Davenport and her husband Jon Leach.
Keys extended her record against Cibulkova to 3-0.