Opting for Scotch game, Madhurima exhibited sheer end game skills to overpower her higher rated Tamilnadu rival in 43 moves.
Meanwhile other overnight joint leaders Tejaswini Sagar of Maharahstra and M Mahalakshmi of Tamilnadu shook their hands after first time control of 40 moves, signaling a draw on result.
In other important fourth round encounters, top seed Chandika Divyasree of Andhra Pradesh escaped from the claws of defeat to split the point against Harini S of Tamilnadu while Swati Mohota of West Bengal outwitted second seed Rucha Pujari of Maharahstra in closely contested game.
Third seed Nimmy A G of Kerala got better off team mate Meenu Rajendran and paired with Madhurima on top board for the fifth round which is now underway at the time of report.