On an eventful day, Mishra won all three of his rounds comfortably to sit atop the table with five points.
Playing white, Mishra outwitted young and talented youngster Mitrabha Guha in 24 moves in a Nimzo Indian defence to secure his third win.
Earlier in the day, he had beaten Sukanya Dutta, while Deborshi Mukherjee had put up spirited resistance against Mishra but only to go down in 29 moves.
Meanwhile, unfancied Arpan Das upset IM Diptayan Ghosh, who will face the sole leader Mishra tomorrow.
He had little difficulty in getting the better of H Venkatesh and Dipanjan Choudhury in the third and fourth rounds, respectively, while in the fifth round he outwitted Arpan Das.
He will face Kaustav Kundu in the penultimate round.