The Scotsman entered the third round in a share of the lead and made two birdies on the front nine to get to 11 under, one clear of Italy's Guido Migliozzi.
Finnish trio Mikko Korhonen, Kalle Samooja and Sami Valimaki, Dane Rasmus Højgaard, England's Callum Shinkwin, Frenchman Clément Sordet and South Africa's Brandon Stone were then at nine under on a bunched leaderboard.
Scot Gallacher is the reigning Hero Indian Open champion but his victory in New Delhi was his only top ten on the 2019 Race to Dubai.
Migliozzi was the first round leader in the desert and enjoyed a stunning 2019 season, winning twice in his rookie campaign.
The 23-year-old got off to a flying start, holing from 12 feet at the first, registering another gain on the next and making a ten footer to take advantage of the par five third and join the lead.
Gallacher also birdied the second and joint overnight leader Højgaard made the most of the third but Migliozzi joined them again with a stunning tee shot to eight feet at the fifth.
A 15 footer from Gallacher on the same hole edged him back ahead and Migliozzi made an excellent par save on the sixth, holing from 15 feet after having to play his second from the rough while stood in a bunker.
Højgaard got plugged in the face of a bunker off the tee at the sixth to surrender a first bogey of the day and a double on the next sent him tumbling down the leaderboard.
He bounced back in excellent fashion, however, making gains on the eighth and ninth to get back into the swelling group at nine under.
Sordet and Valimaki were both six under for the day through 13 holes, while Korhonen had picked up five shots in his first 12.
Shinkwin was four under through ten, Stone was three under having played the same amount of holes, and Samooja - the remaining member of the final group - had a single birdie on the third.