Top tennis seed and former world No 1 Maria Sharapova is out of the ASB Classic after losing to Hungarian Greta Arn in straight sets.
The 23-year-old Russian was in trouble early, with Arn breaking her serve in the opening game in Auckland on Thursday.
Sharapova continued to struggle with the strong serve and forehand of the 31-year-old player ranked 88th in the world, and Arn cruised to a 6-2 win in the first set.
It looked as if Sharapova would take the match to three sets, but she continued to make unforced errors, enabling the unseeded Arn to break her serve again to level the set 5-5.
Arn then broke Sharapova again before holding her nerve to take the set 7-5 and the match, clinching the first semifinal spot at the tournament.
Arn has not won a single tournament in her 15 years on the WTA tour and only gained direct entry to the ASB Classic after late withdrawals.
She says she could barely contain her nerves as she served for the match. "I was just shaking ... I started to think I can beat Maria Sharapova."
The Russian was gracious in defeat, saying it just wasn't her day.
"I started off really slow, got down two breaks and I think she gained a tremendous amount of confidence and played with that throughout the match.
"I had my chances in the second (set) but then didn't play the same way that I played to get there. I gave myself the chances, but I think I let her back in the second set."
Arn will play fourth seed Julia Goerges in the semifinals after the German beat unseeded Kateryna Bondarenko, of Ukraine, 7-5 6-2 6-2.
Defending champion Yanina Wickmayer sent a strong message to the other contenders, thrashing Romania's Simona Halep 6-0 6-2.
The Belgian will play Shuai Peng in the semifinals after the Chinese 17th seed beat Heather Watson, of Great Britain, 6-4 7-5.
Erakovic in doubles semi
In the doubles, New Zealand's Marina Erakovic is through to the semi-finals.
Erakovic and Swedish partner Sofia Arviddson defeated the South African Natalie Grandin and Vladmira Uhlirova, of the Czech Republic, 7-6 6-3 on Thursday.