Playing the white side of a Ragozin defense, Vijayalakshmi went for a routine variation but capitalised on an early queen exchange to put pressure on Zhongyi.
The Chinese just could not handle the threats in the queen less middle game and lost a rook for a minor piece after which it was easy pickings for Vijayalakshmi.
With her fourth victory beside two draws, Vijayalakshmi took her tally to five points out of a possible six and now shares the lead with Iran's Mitra Hejazipour, who toppled overnight leader Aulia Medina Warda of Indonesia.
Mary Ann defeated Wang Jue of China in a keenly contested game of the day.
Among other Indian eves in the fray, Soumya Swaminathan raised visions of an improved finish defeating Shamima Akter Liza of Bangladesh. Soumya moved to four points in all.
In the open section being held simultaneously, Grandmaster Surya Shekhar Ganguly continued to lead the tables jointly, following an easy draw with International Master Lin Chen of China.
Ganguly and Lin Chen remain the only two leaders in this section with five points each in their kitty.
Gupta was pushed to the wall in the endgame and only a very skilled defense could salvage a half point for the Indian.
With two leaders in front on five points, Gupta, Vidit Gujrathi S P Sethuraman, local star A R Salem Saleh and Quang Liem share the third spot on 4.5 points each and it is very likely that the podium will be decided between these contestants.
