Petra Kvitova failed to replace Caroline Wozniacki as world number one as she lost to Li Na in the semi-finals of the Sydney International.
Kvitova, 21, won Wimbledon, the WTA Tour Championships and four other WTA titles in 2011, and would have toppled Wozniacki if she had won in Sydney.
But defending champion Li weathered a fine start by her Czech opponent, eventually winning 1-6 7-5 6-2.
The Australian Open, the year's first Grand Slam, starts on 16 January.
"This match we played today was great for my preparation," said Kvitova.
"The next one is Melbourne, so hopefully I will be better and not really as tired as now."
Wozniacki injured her wrist during her quarter-final loss to Agnieszka Radwanska in Sydney but expects to be fit for the Australian Open.