Flavia Pennetta endured an unhappy birthday as she was dumped out of the Qatar Open by Agnieszka Radwanska in less than an hour on Wednesday.
Pennetta had won the last two meetings between the pair in straight sets, but fourth seed Radwanska saw off the Italian in 49 minutes in Doha, winning 6-1 6-1.
After booking a place in her first quarter-final of the year, Radwanska - a semi-finalist on four of her past five appearances at this WTA Premier event - said: "It actually surprised me as well. For sure I didn't think it was going to be that quick.
"But I think I really played great tennis out there. I was really aggressive from the beginning and really focused from the beginning, and that worked until the end of the match."
Radwanska will now meet Venus Williams in the last eight.
Fifth seed Ekaterina Makarova became the biggest casualty of the event so far as she lost 6-2 6-7 (5-7) 6-3 to Lucie Safarova, who will now face Andrea Petkovic - a 5-7 6-2 6-4 victor over Zarina Diyas.
Petra Kvitova and Caroline Wozniacki - the top two seeds in Qatar this week - benefited from their opponents' misfortune as they progressed past Jelena Jankovic and Alexandra Dulgheru, both of whom retired hurt.
In the final two matches, Victoria Azarenka beat Elina Svitolina 6-3 6-7 (4-7) 6-1, while Carla Suarez Navarro overcame Karolina Pliskova 7-6 (7-2) 6-4.