Two days after her upset win over Venus Williams, Belinda Bencic is out of the Australian Open.
Bencic was on a high after beating 2017 finalist Williams on the center court in the first round, but started flatly on Hisense Arena on Wednesday and lost 6-1, 6-3 to powerful hitting Thai qualifier Luksika Kumkhum.
The 20-year-old Swiss, who combined with Roger Federer to win the Hopman Cup in the lead-up to the season's first major, saved three match points on her serve before netting a backhand to give No. 124th-ranked Kumkhum a spot in the third round for the first time.
A 15-year-old qualifier and the No. 4-seeded Elina Svitolina were among three Ukrainian women who had matches starting simultaneously on Day 3 - and all progressed to the third round.
Former Australian junior champion Marta Kostyuk, who entered the season-opening major ranked No. 521, followed up her opening win over 25th-seeded Peng Shuai with a 6-3, 7-5 victory over wild-card entry Olivia Rogowska.
Kostyuk already is the youngest player since Martina Hingis in 1996 to win a main-draw match at the year's opening major. And that came after three three-set matches in qualifying over six hours.
Kostyuk is managed by Ivan Ljubicic, who works with Federer, and so gets the benefit of some first-rate analysis.
"Ivan is always helping me ... after every match, he's telling me what's wrong," she said, smiling.
Kostyuk's progress is set to become more difficult, with a meeting against Svitolina in the next round.
While Kostyuk was playing on Margaret Court Arena, Svitolina, who won a tour-leading five titles in 2017, had a 4-6, 6-2, 6-1 win over Katerina Siniakova on the adjoining Rod Laver Arena.
Their fellow Ukrainian, Kateryna Bondarenko, beat No. 15-seeded Anastasia Pavlyuchenkova 6-2, 6-3 in the day's opening match on Melbourne Park's third show court to reach the third round here for the third time.
On the men's side, No. 10 Pablo Carreno Busta was leading 6-2, 3-0 when Gilles Simon retired from their second-round match with a leg injury.
Andreas Seppi beat Yoshihito Nishioka 6-1, 6-3, 6-4.