Teenaged tennis star Ashleigh Barty has failed to replicate her heroics of last year in the Australian Open wildcard play-off at Melbourne Park.
The 16-year-old Queenslander, who won last year's play-off, was upset by Serbian-born West Australian Bojana Bobusic in their quarter-final on Thursday.
Bobusic, who as world No.334 is ranked 158 places lower than Barty, withstood a strong start by the No.2 seed and fought back in hot conditions for a 3-6 6-3 6-4 win.
Barty is almost certain to be granted a discretionary wildcard despite the defeat.
Bobusic's victory set up a meeting with Victoria's Arina Rodionova - the sister of fellow professional Anastasia Rodionova - in Saturday's semi-finals.
Rodionova beat WA's Jessica Moore 7-5 6-3 on Thursday.
NSW's third seed Monique Adamczak, the highest-ranked player left in the event after Barty's exit, downed Victoria's Viktorija Rajicic 6-2 6-4.
Adamczak's semi-final opponent is yet to be decided, after rain stopped play between Priscilla Hon (Qld) and Tammi Patterson (Vic), with Hon 4-3 up in the first set.
They will resume on Friday.
Patterson upset top seed Olivia Rogowska in the opening round.
The men's semi-finals are on Friday, with Queensland's John-Patrick Smith to meet NSW's Matt Reid and Queenslander Benjamin Mitchell to face NSW's Matthew Barton.
The winners of Sunday's men's and women's finals will gain direct entry to January's grand slam event.