In her first competitive match since winning the doubles gold at the Glasgow Commonwealth Games, Pallikal held her nerve to beat Denmark's Hansen 9-11 11-4 12-10 5-11 11-6 in 56 minutes.
Pallikal, who has slipped out of top-10 to be 12th in the latest rankings, next faces an unexpected opponent in qualifier Salma Hany Ibrahim.
The Egyptian stunned World No.6 Alison Waters of England 11-7 3-11 11-8 11-3 in another opening round match.
Pallikal lost to World No.1 Nicol David in the quarterfinals here in 2013. The Indian doesn't plan to play anymore tournaments before the Incheon Asian Games beginning September 19.