Ratchanok's title defence campaign collapses in India

The defending champion was up-and-down throughout the match which was their 14 th career meet with the South Korean world No 4 wining their latest encounter  21-19 21-12 in Dubai Masters in December.

The 22-year-old world No 7 who won twice in 2013 and 2016 was neck-and-neck with the second seeded Sung until 15 all in the first game. But from then on, Ratchanok let a series of easy mistakes come out of her racquets to face a game point at 15-20.

While chasing a shot in the next point, the Thai slipped and twisted her right ankle which raised concerns from the stadium. But she returned to the court and fought off four match points before Sung finished her off with a quick attack.

Ratchanok is in her second tournament after several months of injury break. She will have to defend her crowns in Singapore next week and in Malaysia the next two weeks.