Maria Sharapova continued her untroubled progress at the Qatar Open on Friday, brushing aside Australia's Samantha Stosur 6-2 6-4 to reach the semi-finals.
The Russian, who began the week with the possibility of reclaiming the world number one ranking, has not dropped a set in her three matches, a feat equalled by world number one Victoria Azarenka who saw off Italian Sara Errani 6-2 6-2.
American Serena Williams, 31, will return to the top of the rankings if she beats Petra Kvitova later on Friday to set up a semi-final showdown with Sharapova.
Should 15-times grand slam champion Williams beat the Czech she will go back to number one for the first time since October 2010 and become the oldest woman to top the rankings.
Sharapova held an 11-2 career record over Stosur and was never threatened during an 82-minute victory.
Australian Open champion Azarenka's hopes of holding on to the top ranking are out of her hands, even if she wins the title.
(Reporting by Martyn Herman, editing by Tony Jimenez)