The 24-year-old clocked four minutes and 38.27 seconds in the opening heat to beat her previous time of 4:38.83 set in winning the event in New Delhi four years ago, reports BBC.
"I was hoping to go in 4:40 so it's a lot quicker than I expected," she told BBC Sport. "Normally you feel the pressure but I loved every second."
The final for the event will take place later in the day.
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