The India-South Africa match-up was between the last placed teams in the two preliminary groups.
India had lost all their five pool matches and today's loss to South Africa completed the most miserable show at the Olympics for the eight-time gold medallists, who in 2008 had failed to qualify for the Beijing Games.
India were placed 10th in the world rankings ahead of the Olympic Games.
The Indian team got the bronze medal at the Azlan Shah Cup in Malaysia two months ago, but Chetri said experience was key to success in a top-notch event like the Olympic Games.
"We need to be better prepared for such events, where experience seems to matter a lot more than we thought," said the Indian custodian who did not play on Saturday.
"Though we thought ourselves to be a good team, we failed to justify the expectations," he said.
"What we saw and learnt here was quite different from the past tournaments in which we had participated," Chetri added.
Vice-captain Sardar Singh, who emerged as India's best player in the disastrous campaign, said numerous missed chances in every game hurt the team badly.