The Indian lost 2-6 4-6 to 12th-seeded Radwanska in a one hour and 16 minute contest at the Roland Garros here.
It was always going to be tough for World No. 72 Sania as she committed 42 unforced errors as compared to her opponent's 18. Sania though hit more winners than Radwanska.
The Polish player completely dominated the proceeding to run away with the first set 6-2.
In the second set, Sania, who does not like clay court surface, lifted herself but Radwanska proved to be too strong for her.
Sania has not been able to cross the second round hurdle in the Grand Slams since 2009 and the fourth round appearance in the US Open in 2005 remains her best performance.
Sania's campaign, however, is not finished in French Open as she and her partner Elena Vesnina have reached the second round of the women's doubles.
