Playing white side of Nimzo Indian defence, Priyamvada capitalised the crucial mistake committed by Ivana in the 34th move to secure victory in 50 moves.
Meanwhile, second seed Indian girl V Varshini also got a minor setback as she was forced to sign the peace treaty with Maya Yalkanova of Turkmenistan.
In the open category, Indian Grandmaster trio of Aravindh Chithambaram, Karthikeyan Murali and S L Narayanan registered easy victories in the first round against Avik Sarker, Adhithya S and Srijit Paul respectively.
Important Results (Indian otherwise stated):
Open Round 1: GM Aravindh Chithamabaram (1) beat Avik Sarker of Bangladesh (0); Adhithya S lost to GM Karthikeyan Murali (1); GM S L Narayanan (1) beat Srijit Paul (0); Baivab Mishra (0) lost to IM Masoud Mosadeghpour of Iran (1); IM Mousavi Seyed Khalil of Iran (1) beat Hemanth Raam (0); Subhayan Kundu (0.5) drew with FM Nima Javanbakht of Iran (0.5); FM Karthik V (1) beat Rajesh Nayak (0); Anish Gandhi (0.5) drew with Arjun Kalayan (0.5); Harsha Bharathakoti (1) beat Rustem Nazarov of Turkmenistan (0); Saksham Rautela (0) lost to Rahul Srivatshav P (1).