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, by losing two sets and winning one while the rest two ended in ties.
The Indian lost 28-30, 30-28, 27-27, 27-28 28-28 to bring to an end the country's medal-less campaign.
Das seemed to lose his nerve on a couple of occasions and missed out on capitalising on positions of strength against the world No.8 Korean who shot a hat-trick of perfect 10s in the opening set.
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.
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The third set ended up being a tie before Lee nosed ahead by grabbing the fourth set.
But Atanu could only strike a 9, which was enough to tie the fifth set 28-28 but insufficient to save the match.
The script was no different in another precision sport, shooting, where seasoned Narang and Chain Singh flopped in the prone position of the 50m rifle event.
It was particularly disappointing for Narang, who was placed as high as 4th at one stage. However, he bungled the advantage by shooting his poorest in the sixth and final series, which yielded him his lowest score of 102.4.
Singh, on the other hand, never seemed to be in the reckoning after losing the plot in his second and fourth series, which fetched him scores of 101 and 102.4.
His subsequent efforts at salvaging the situation could not save him from a free-fall on the leaderboard. Singh shot a series of 104.1, 101.0, 104.4, 102.4, 103.9, 103.8.
Narang and Singh will still have a shot at redemption on Sunday, the final day of shooting, when they take aim in the 50m Rifle 3 Position event.
Touted as the brightest medal hopes for the country, the shooters have been way off the mark at the mega-event.