The Indian, ranked 160th, beat her opponent 10 places below her in WTA chart, 6-3 6-3 in one hour and 19 minutes to advance to the third and final round.
Sania broke her rival twice in four chances and saved two break points on her own serve to go one set up.
In the second set, the Indian dropped her serve once but negated it by breaking Elena, who reached US Open quarterfinals in 2002, twice to clinch the issue.
She will next face Columbia's Catalina Castano, ranked 188th in the world.
Her low ranking forced Sania to go through the qualifiers of a Grand Slam for the first time after her breakthrough year at Australian Open in 2005.
Published 27 August 2010, 06:25 IST