Basel: Indian shuttler H S Prannoy today registered a stunning upset victory over seventh seed Boonsak Ponsana of Thailand to storm into the pre-quarterfinals of the Swiss Open Badminton Championship here.
Unseeded Prannoy came from a game down to beat his much-fancied opponent 18-21 21-13 21-12 in a 55-minute second round contest.
Prannoy had beaten Michael Lahnsteiner of Austria 18-21 21-9 21-12 in the first round.
The world number 97 Indian next takes on 15th seed Tien Chen Chou of Chinese Taipei in the round of 16.
Earlier, world number nine and fifth seed Indian Parupalli Kashyap entered the second round with a comfortable 21-7 21-19 victory over Hsuan Yi Hsueh of Chinese Taipei.
However, Sourabh Varma and K Srikanth ended their campaign in the first round of the tier three tournament at at St Jakobshalle.
London Olympics quarterfinalist Kashyap will take on Germany`s Dieter Domke in the second round.