DOHA, Qatar (AFP) — Naomi Osaka's hopes of clinching the Qatar Open ended in a straight-sets quarterfinal loss to fellow former world No. 1 Karolina Pliskova on Thursday.

Four-time Grand Slam title winner Osaka, who is rebuilding her career after maternity leave, went down 7-6 (8/6), 7-6 (7/5) after saving three match points.

It was the 26-year-old Japanese star's second defeat to Pliskova this year after losing in three sets in her comeback tournament in Brisbane last month.

Pliskova, ranked at 59, will face world No. 1 Iga Swiatek for a place in Saturday's final.

The Czech's win over Osaka, clinched in one hour and 43 minutes, was her ninth in the last 10 days, a run which included the Transylvania Open title on Sunday.

Defending champion Swiatek moved closer to a third successive Qatar title when she brushed aside Victoria Azarenka 6-4, 6-0 in 74 minutes in her quarterfinal.

The 22-year-old Swiatek is 12-1 at the Gulf tournament with her only defeat coming in the 2020 second round to Svetlana Kuznetsova.

"I felt like I started a little bit too aggressively maybe, but then I found my rhythm and the proper way to play," Swiatek said.

"I kept it till the end of the match. I'm happy that I could analyze during the match and then take a lesson from that."

Former world No. 1 Azarenka, the 2012 and 2013 champion in Doha, double-faulted in the ninth game to hand Swiatek the first break.

The top seed served it out before racing through the second set without facing a breakpoint.

Swiatek ended the encounter with 17 winners to just five from Azarenka.

Earlier, Elena Rybakina and Anastasia Pavlyuchenkova set-up a semifinal clash.

Third seed and former Wimbledon champion Rybakina came from 4-2 down in the first set to defeat 2021 US Open finalist Leylah Fernandez 6-4, 6-2.