Safina, who lost a three-set decision to Dementieva in an all-Russian final at the Medibank International last year, lost five of eight service games in falling 6-2, 6-3 in this year's quarterfinals to the fifth-seeded Dementieva.
Dementieva won more points (30-26) on Safina's serve than the world No. 2 did. Safina has lost four of her last six matches, dating to last September.
American Serena Williams, the No. 1 women's player in the world, was on the court just 61 minutes in a 6-2, 6-2 rout of Vera Dushevina. Williams lost only 10 points over eight service games.
No. 6-seeded Belarusian Victoria Azarenka rallied for a 2-6, 6-2, 7-5 win over Slovak Dominika Cibulkova and France's Aravane Rezai was a 6-3, 6-0 winner over Italian Flavia Pennetta in Wednesday's other matches.
Thursday's semifinals have Williams going against Rezai in a first-time pairing and Dementieva playing Azarenka. Dementieva has won two of the three times she's played Azarenka.
Copyright 2010 by United Press International.