The match was delayed for 3 hours by rain at the Bukit Kiara Equestrian and Country Resort. Rybarikova held serve only once in the 62-minute match.
"It was tough on both of us to wait so long to begin the match, but I think it affected her more as she had a very slow start to the game," Dementieva said. "I'm just thankful to have finished the match in two sets."
Dementieva will play sixth-seeded Sybille Bammer, who rallied to defeat Chang Kai Chen 6-3, 3-6, 6-3 after a rain delay.
Rodionova was involved in a running argument with the chair umpire and line judges, allowing her frustrations to affect her game.
The 19-year-old Ayumi, who reached her first WTA semifinal, will seek to avenge her loss to Kleybanova in their first meeting four months ago at the Tokyo Open.