Though she is a 4th seed here, the Goa representative was absolutely an outsider in the favourite list before start of the tournament.
Riya on Monday stole the limelight with a stunning performance.
However, Mahalakshmi's fall means Varshini Velavan's (6.5) gain, who in the earlier round beat second seed GK Monnisha.
Varshini (7.5) now jumped to the top of the table with a win over Shiny Das (5.5) of Tripura.
Monnisha (7) on Monday beat CH Meghna (6) of Kerala to join the second position with Mahalakshmi.
A tensed draw with B Kumaran (7) in the 9th round of the of the National Sub Junior Chess Championship for Boys and Girls, organized by Bengal Chess Association, IM Murali Karthikeyan (7.5) remained sole leader in the boys section.
Half point adrift Kumaran, IM Diptayan Ghosh (7), Sidhant Mohapatra (7), Arvindh Chithambaram (7), Harsha Bharathakoti (7) jointly followed the leader.
In the top two boards, Kumaran-Karthikeyan and Diptaya-Sidhant Mohapatra failed to break opponents defence, both settle for splitting point.
Third seed Arvind and 11th seed Harsha of Ap beat Md Nubairshah Sk (6) of Maharashtra and Al Muthaiah (6) of Tamil Nadu respectively.
--IBNS (Posted on 13-08-2013)