A misfiring Maria Sharapova has been upset by American qualifier Jennifer Brady in the first round of the Brisbane International.
The five-time grand slam champion served 11 double faults to the world No.53's one to crash out 3-6 6-1 7-6 (7-4) in a clash lasting more than two hours.
Sharapova may be one of the tournament's biggest names but had to rely on a wildcard to contest the season opener after her ranking slumped to 147 following an injury-plagued 2019.
However, she didn't look troubled by her recurring shoulder complaint when she cruised through the first set.
But Brady hit back to book a second round clash with Australia's world No.1 Ashleigh Barty.
Earlier, dual Wimbledon champion Petra Kvitova avoided becoming a high profile scalp, surviving an early scare to down Russian Anastasia Pavlyuchenkova.
Fifth seed Kvitova of the Czech Republic overcame a nervous start to overpower Pavlyuchenkova 2-6 6-1 6-0 in just over an hour and a half.
World No.7 Kvitova, a former Brisbane champion, was expected to hit the ground running on Tuesday night.
However, another upset loomed when world No.29 Pavlyuchenkova came out swinging against the 2019 Australian Open finalist.
In the end Kvitova found her range to extend her head to head career record against the Russian to 8-4, but former US Open champion Sloane Stephens wasn't so lucky.
Russian qualifier Liudmila Samsonova produced the upset of the tournament to date, defeating world No.24 Stephens of the USA 6-4 2-6 6-3.
World No.129 Samsonova - making her Brisbane debut - will now take on Kvitova in the second round.
Stephens joined three-time grand slam champion Angelique Kerber, fourth seed Elina Svitolina and now Sharapova as stars to fall to date in the season opener.
But defending Australian Open champion Naomi Osaka made a winning start to her summer, defeating Greece's Maria Sakkari 6-2 6-7 (4-7) 6-3 to set up a second-round encounter with American Sofia Kenin.
American eighth seed Madison Keys eased past Czech qualifier Maria Bouzkova 6-3 6-2 and will now face local favourite Samantha Stosur in the second round.
"Sam's always tough," Keys said.
"It's also hard to play someone who is going to be playing at home and have the crowd and all that."
In other matches, sixth seed Kiki Bertens of the Netherlands overcame Dayana Yastremska of the Ukraine in three sets to book a second round clash with Anett Kontaveit.
Estonia's Kontaveit was too good for Taiwan's Su-Wei Hsieh on Tuesday.
And qualifier Yulia Putintseva of Kazakhstan upset world No.20 Donna Vekic of Croatia 6-3 3-6 7-5 to book a second round clash with Svitolina's conqueror, American Danielle Collins.