World No.1 Angelique Kerber will start her Australian Open defence short of confidence and match practice after making an error-riddled exit from the Sydney International on Tuesday.
Russian teen Daria Kasatkina was far too composed in her second meeting with Kerber, who won grand slams in Melbourne and New York last year to claim top spot on the women's rankings.
Kasatkina triumphed 7-6 (7-5) 6-2 in 92 minutes, storming into the third round of the Sydney tournament by breaking the top seed's serve on five occasions.
Kerber's form since landing in Australia has been unconvincing. At last week's Brisbane International she recorded a three-set win over Ashleigh Barty then a three-set loss to Elina Svitolina.
The German, who last year secured her first grand slam title by stunning six-time Open champion Serena Williams at Melbourne Park, admits something is amiss.
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"The first matches of the year are always tough and I still don't feel my rhythm. I made too many mistakes," Kerber said of her 41 unforced errors, including a loose stroke that resulted in Kasatkina taking the first-set tiebreak.
"So it was not so easy, but I will try to forget the match as soon as I can.
"It's the second tournament of the year. We have still a lot to go, so I will not do a big drama about that match."
The NSW heatwave, which resulted in temperatures of 36.3C at Homebush, could be one factor in explaining her meek surrender to Kasatkina.
But Kerber was in no mood to make excuses as he she weighed up how best to prepare for the Open.
"At the beginning of the match it was really hot, but it's always like that here," she said.
"And in Melbourne, could be the same.
"The heat is, of course, still a little bit difficult ... but I have one week more before the grand slam and this is the important tournament."
Kasatkina, who last week pushed 2016 French Open champion Garbine Muguruza to a third-set tiebreak in an engaging three-hour contest, confirmed she will be one to watch at next week's Open.
Kasatkina, who never looked back after defusing three break points to take a 4-2 lead in the second set, next faces Sydney-born Brit Johanna Konta.
Sixth seed Konta crushed local hope Daria Gavrilova 6-1 6-3 on Tuesday, while the final match of the night was second seed Agnieszka Radwanska's 7-6 (7-1) 6-1 win over Christina McHale.
Defending Sydney International champion Svetlana Kuznetsova was ousted by Russian compatriot Anastasia Pavlyuchenkova, while world No.6 Dominika Cibulkova and No.18 Roberta Vinci were also defeated.
Pavlyuchenkova beat world No.9 Kuznetsova 7-5 6-3 and now meets 2014 Wimbledon finalist Eugenie Bouchard, who downed Cibulkova 6-4 6-3.
