B Kumaran, with white pieces, produced an interesting and lively game to beat his Southern Railways rival.
In another upset result Vasantha Rubavarman outplayed woman Grandmaster and IM Vijayalakshmi Subbaraman.
Multiple National Champion R Vaishali, who had recently clinched a medal at the World Youth Chess Championships, outplayed Bangladeshi Grandmaster Ziaur Rahman in 50 moves.
Chennai lad Vasantha Rubavarman outplayed Vijayalakshmi Subbaraman from the white side of a Ruy Lopez Breyer variation.
The Chennai based Grandmaster, Sethuraman, tried the recently popular third move Qd6 in the Scandinavian defence, possibly in a bid to avoid any theoretical preparation by his opponent.
But the Orissa girl showed her class as she slowly but steadily built up a huge advantage. In the end, after a long and gruelling 147 moves, Sethuraman threw in the towel after Padmini exhibited her skill and knowledge in winning a Bishop and Knight ending.
Six players share the lead with four full points at the end of the fourth round. More