The Republic of Korea archer, who shot 671 in the ranking round to top the scoresheets, had two straightforward matches yesterday but was paired with Japan's team bronze medallist Hayakawa in the last 16.
Ki began with an uncharacteristic eight and after both archers shot nine and 10, Hayakawa was left needing nine for the set.
Instead, she aimed too high and shot seven.
Ki did not offer another chance, dropping just one point in the second set and two in the third for a decisive 6-0 win.
An early six cost Perova the opening set and, after a tied second, another stray six left her staring at a defeat at 5-1 down.
But Perova was imperious thereafter, shooting a perfect set of 30 and then reeling off 10, nine, nine to force a deciding arrow.
Rochmawati, the Indonesian outsider who surprised Fang Yuting in the first round, hit nine but Perova struck centre gold.
Ki's Korean team-mate, second seed Lee Sung-jin, also had an emphatic win.
Paired with Mongolia's Bishindee Urantungalag, she shot sets of 29, 26 and 27 to progress from the last 16 in nine arrows.
Mariana Avitia, of Mexico, awaits Lee after she brushed aside a wayward Carina Christiansen 6-2.
The Dane, on top form yesterday, missed the target entirely with her second arrow and consistently shot wide left as her scores were well down.
Choi lost the first set with a costly seven but got on the scoreboard with a halved set of 28 points apiece.
Schuh took a 5-1 lead when she struck nine, nine, 10 but Choi claimed the next four set points as she steadied her aim.
Both of Choi's matches yesterday were won on a shootout but this time the format failed her as both women struck nine and Schuh was measured closer.