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.
Alisa Kleybanova overcame Anastasia Rodionova 4-6, 6-3, 6-4 to reach the other semifinal.
Rodionova was involved in a running argument with the chair umpire and line judges, allowing her frustrations to affect her game.
Kleybanova will play unseeded Ayumi Morita, who defeated Chanelle Scheepers 6-3, 7-5.
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.
Ronaldo aims for double gloryDjokovic to face Baghdatis in Dubai semifinal
