World number one Carolina Marin and number two Saina Nehwal both lost their final round robin matches at the Dubai World Superseries Finals on Friday.
Marin, who is the favourite to lift the trophy this year, came unstuck against gritty Japanese competitor Nozomi Okuhara, going down 21-9, 21-15.
It was her second defeat in two days after she also lost to Nehwal on Thursday.
"I didn't prepare so well for my match with Saina," said the Spaniard. "And today I made far too many mistakes. I'm very disappointed.
"I'm now going off to do more training."
Marin looked almost certain to exit the competition, as her survival now relied on Nehwal losing to Chinese Taipei's Tai Tzu Ying, a result that seemed highly unlikely.
However, Friday turned out to be a day of upsets at the Indian shuttler did indeed go down, winning the first game but losing the next two as Tai completed a surprise 16-21, 21-18, 21-14 victory.
The results mean that the undefeated Okuhara and Marin are the two ladies to go through to the semi-finals from Group A.
In Group B, Thailand's Ratchanok Intanon secured her place in the last four with a 21-14, 21-19 victory over China's Wang Shixian.
She is joined by China's Wang Yihan, who had already booked her passage with two earlier wins in the competition.
Wang lost on Friday, 21-14, 21-11 to Sung Ji Hyun of South Korea, but the result was of no consequence.