With reigning world champion Denisse van Lamoen falling at the same hurdle yesterday, Amy Oliver of hosts Great Britain ensured another big shock.
The Indian was short of her best when she placed eighth in the ranking round, but was still expected to go past Oliver, who is 37th in the world.
But she failed to hit a single 10 in four sets and Oliver sealed the upset with back-to-back maximums.
The home favourite could not carry on, though, beaten 7-1 by Ika Yuliana Rochmawati, who had also caused a shock in the last 64.
The Indonesian beat world number three Fang Yuting 6-4 of China, who was slow to find her range and paid the price.
Rochmawati will meet Russia's Ksenia Perova in the last 16.
Perova eased past Nada Kamel in a nine-arrow finish and then took the significant scalp of six-time Olympian Natalia Valeeva 7-3.
Valeeva, who has competed under three different flags since her debut at Barcelona 1992, will now consider whether to pursue a seventh Olympic Games.
'I will take a few months' rest for my family and for my health and then I will think about the next Olympic Games,' she said.
'I knew I needed to fight but I didn't expect what happened today. There were errors.'
There was progress for American Khatuna Lorig, appearing in her fifth Games.
Lorig, who coached actress Jennifer Lawrence for her role in hit film The Hunger Games, outclassed Sherab Zam 6-0 in first elimination.
She then came up against Denmark's Louise Laursen and triumphed 6-4. Laursen had earlier ousted Canada's Marie-Pier Beaudet 7-3.