Johanna Konta saw her Sydney International title defence swiftly ended as she lost to Agnieszka Radwanska in the first round.
A surprising slide in the rankings to 28th meant former world number two Radwanska entered this week as an unseeded player, but she showed her quality in a 6-3 7-5 victory over British hope Konta.
In a repeat of last year's final match-up, this time fourth seed Konta could not take control of the contest against Poland's former Wimbledon runner-up.
Consolation for Konta came with the fact she completed the match without obvious physical problems, five days after being forced to retire from her Brisbane International quarter-final with Elina Svitolina due to injury.
She now heads for Melbourne and the Australian Open, where 12 months ago she reached the quarter-finals, while Radwanska continues her grand slam preparation in Sydney and faces American teenager CiCi Bellis next.
Konta is 16/1 for the Australian Open title with Sky Bet, who make Radwanska a 50/1 chance.
Radwanska said of her win, according to wtatennis.com: "I'm just so happy to play such a great match before the Australian Open.
"It was a top-10 level match with some ups and downs, breaks along the way. The conditions weren't easy, but I'm happy to win in two sets."
American Venus Williams was the casualty of a heavyweight second-round clash with Germany's former world number one Angelique Kerber, starting well but running out of steam in losing 5-7 6-3 6-1 shortly before midnight.
Rain had held up play earlier, after wins for Slovakian Dominika Cibulkova, Czech Barbora Strycova and Australian Samantha Stosur.
Ashleigh Barty overcame Ellen Perez 7-6 (7/4) 6-1 in an all-Australian battle after the rain passed over, and in another Daria Gavrilova edged out Olivia Rogowska 6-4 1-6 7-5.
There were no such problematic weather interruptions at the Hobart International.
Belgian second seed and defending champion Elise Mertens was a 6-4 6-4 winner against Brazilian Beatriz Haddad Maia, and Ukrainian fifth seed Lesia Tsurenko also advanced with a 6-3 6-2 victory over Kazakhstan's Yulia Putintseva. Both were second-round matches.
Two seeds slumped to first-round defeats. Romanian qualifier Monica Niculescu ousted her sixth-seeded compatriot Irina-Camelia Begu 6-3 6-2, and Czech eighth seed Katerina Siniakova fell 2-6 6-3 7-5 to American Alison Riske.