The men's individual archery tournament nearly saw a big upset on Tuesday as second-seeded South Korean Kim Bubmin was pushed to the brink by Fiji's Robert Elder.
Elder, seeded 63rd, lost the first two sets against Kim, but rebounded to win the next two 29-27 and 27-26. Kim, though, recovered to take the final set 26-23 and then advanced into the 1/8 eliminations with an easier victory over India's Tarundeep Rai.
For the United States, 2012 team silver medalist Jacob Wukie won his opener in straight sets, but was then eliminated in the following round by Norway's Baard Nesteng.
Wukie's teammates Brady Ellison and Jake Kaminski play their first matches on Wednesday.
Michele Frangilli, who won team gold in London with Italy, was knocked out in the first round.
On the women's side, 2011 world champion and Chilean flag bearer Denisse van Lamoen lost her 1/32 eliminations match, while Great Britain's Naomi Folkard and Alison Williamson both failed to reach the 1/8 eliminations.
The United States' Jennifer Nichols won her first match before getting bounced out the following round.