Double Olympic medallist PV Sindhu failed to defend her Swiss Open Super 300 badminton title as she was shocked by unseeded Putri Kusuma Wardani of Indonesia in a thrilling three-game women's singles second round match here.

World no.9 Sindhu, seeded fourth here, was stunned 15-21 21-12 18-21 by the 38th ranked Wardani in their first-ever face-off at the international level on Thursday night.