Seventh-seeded Elena Dementieva pulled the surprise of the day by taking down second-seeded Vera Zvonareva 7-5, 6-2 in the Pan Pacific Open quarterfinals Thursday.

The victory prevented Zvonareva from overtaking Venus Williams for the No. 3 spot in the rankings. Other top seeds held serve Tin Tokyo, giving the Pan Pacific Open a final four of women all ranked in the world’s Top 11.

Top-seeded Caroline Wozniacki had the easiest time, advancing in a walkover when sixth-seeded Agnieszka Radwanska retired with a left foot injury while trailing 0-5 in the first set. Wozniacki will take on eighth-seeded Victoria Azarenka, who easily dismissed American qualifier Coco Vandeweghe 6-2, 6-1.

Azarenka is 2-2 all-time against Wozniacki. The pair last played last November at the Tour Championships, with Wozniacki rallying for a 1-6, 6-4, 7-5 win. The other semi-final match pits Francesca Schiavone against Dementieva.

Schiavone had a real tussle on her hands, sweating out a 7-5, 4-6, 7-5 win over Kaia Kanepi, the only other unseeded player in the quarterfinal field. Schiavone has now breached the 5,000-point mark for the season, moving her up to No. 6 in the world, ahead of Samantha Stosur and Jelena Jankovic.

Dementieva has had Zvonareva’s number, winning five of seven matches all-time against her. After losing in the first round last year, Dementieva’s run will move her past Radwanska to No. 9 in the world regardless of how she finishes.