Harika (ELO 2542), who was joint 26th at the start of the match, beat Scotland's GM Ketevan Arakhamia-Grant (2376) to accumulate 3.5 points. She has so far won three games, drawn one and lost one.
The World No. 6 sounded particularly happy after this win.
"It wasn't an easy game. But I keep mounting the pressure on my opponent and it helped," Harika said.
"I slowed gained the initiative and at the right time went for the kill," she added.