Emma Raducanu lost her first match of the year 6-0 6-1 against Elena Rybakina in just 55 minutes at the Sydney Classic.
The British No 1 was playing her first competitive contest under new head coach Torben Beltz, who she appointed in November.
After losing the opening nine games in succession, the 19-year-old got on the board in the 10th game and punched the air in delight.
Rybakina quickly hit back though and despite Raducanu settling slightly, she had left far too much to do.
Raducanu was due to play at last week's Melbourne Summer Set, however put back her competitive return due to Covid-19 having hindered her lead into the 2022 season.
In contrast, Rybakina was match-ready having progressed into the final of the Adelaide International and only being halted by the world No 1 Ashleigh Barty.
After stepping out to a warm reception from the crowd inside the Ken Rosewall Arena, Raducanu went 40-15 up in her opening service game before being reeled back to deuce.
She then saved a break point, before a third double fault of the game handed Rybakina the early advantage and platform.
As the opening set continued, the British No 1 continued to look uncomfortable with the pace of Rybakina's shots.
Raducanu wasn't able to find her rhythm from the back of the court at all, she had little time to direct her responses back to the ninth seed and found herself 4-0, and then 6-0, down.
The start of the second set brought no reprieve for the 19-year-old, who won the US Open in such spectacular fashion last year.
Her determination to continue to try and problem-solve delivered her the 10th game of the contest and helped her save two match points.
However, together with new coach Beltz, Raducanu must work out why Rybakina's power overwhelmed her, how she can counter it and just how she will contend with in-form, experienced tour players like Rybakina on a daily basis.
Raducanu is seeded 17th going into next week's Australian Open; the draw for the opening Grand Slam of the year takes place on Thursday and the competition starts on Monday.
Dart into second round of qualifying
Harriet Dart progressed into the second round of qualifying for the Australian Open.
The 25-year-old produced a 6-4 6-3 victory over Federica Di Sarra and faces American Alycia Parks next.
Samantha Murray Sharan lost out in a final set tie-break against Hailey Baptiste, while Katie Boulter and Jodie Burrage also suffered defeats in qualifying.
Fran Jones retired from her contest with Usue Maitane Arconada at 5-1 down the opening set.