While Gursimar went into lead at the end of first round, the two top stars, Vani Kapoor and Amandeep Drall, who have won five of the eight events this season, had a disappointing start.
Vani shot 77 and Amandeep was further behind with 78.
The 24-year-old Gursimar, who hails from Kapurthala, won in Mumbai in February, 2016.
At the lovely Prestige Golfshire, she did not have a great start with two bogeys on second and third holes and turned in two-over after another bogey on sixth and her first birdie of the day on eighth.
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She birdied the 10th and then found three more in a span of four holes from 14th to 17th besides a bogey on 15th and ended at one-under 71.
Gursimar was two shots clear of amateur Ridhima Dilawari, who also birdied 16th and 17th enroute to a round of 73.
Four players, including amateur Pranavi Urs, Gaurika Bishnoi, who has not finished outside Top-10 this season in any of her eight starts, Neha Triptahi and Mehar Atwal shot 74 each to share the third place.
Siddhi Kapoor was seventh with 75, while Sonam Chugh, Suchitra Ramesh and Afshan Fatima were tied eighth with rounds of 76 each.
Winner of three of the four tournaments she has played on the domestic circuit this season, Vani, had just one birdie on ninth.
She had four other bogeys and a double bogey.
But she has two more rounds to make amends.
Also bringing in a disappointing 78 was Amandeep Drall, who also had just one birdie.
Amandeep, who has won twice and been second four times this year, had five bogeys and one double bogey and was 14th.