He fought valiantly, but ultimately went down 4-6 (28-30, 30-28, 27-27, 27-28, 28-28) at the Sambodromo.
Shooting amid heavy rain, Atanu went down 4-6 to World No.8 Lee Seung-Yun, who had already helped South Korea win the team gold at the event.
It was not a bad performance by the Indian but he did seem to lose his nerve on a couple of occasions and missed out on capitalising on positions of strength.
On expected lines, the Korean shot a hat-trick of perfect 10s in the opening set to clinch it 30-28. However, not to be bogged down, Atanu responded quite well with three successive 10s of his own to unnerve Lee and draw level in the match by taking the second set 30-28.
The third set ended up being a tie before Lee nosed ahead by grabbing the fourth set. In the decisive fifth set, Atanu and Lee were tied 19-19 after the first two shots. Lee managed a 9 off his final arrow and Atanu needed to go one better to take the match into a shoot-off.
But Atanu could only strike a 9, which was enough to tie the fifth set 28-28 but insufficient to save the match.
The disappointed Indian could only rue the missed chances even as the exulted Korean celebrated his narrow escape.
India, thus, ended yet another medal-less campaign in archery at the Games as Laishram Bombayla Devi, Deepika Kumari and Laxmirani Majhi have already bowed out of contention after losing in both the women's team and individual events.
(With inputs from agencies)