Captain Rahul Dravid blamed his team's top order for the defeat, saying they let the team down in the crucial outing.
"We are a little disappointed. We could have batted a lot better," Dravid said after the 174-run loss.
The Karnataka batsman said the bowlers did their job admirably.
"The bowling was good and they set up the match for us, but the batting let us down."
Dravid singled out the devastating spell from Makhaya Ntini (5-48) as the crucial factor in the match.
"Ntini's spell on Saturday was the key. (Ashwell) Prince also batted very well in the first innings in making a century," he said. However, all was not lost for the Indians, Dravid felt.
"We have been competitive over five days and stayed with them. It's exciting to go to Cape Town with the series on the line," the skipper said.
A visibly relieved Graeme Smith credited the win to the intense determination of his team.
"The boys wanted it (the win) badly. They showed a lot of character and it was a top performance. I'm over the moon."
There were lot of negative comments after the debacle in the Johannesburg Test, Smith said.
"There was a lot of unjust criticism. People went to town criticising us but I'm proud of the way we came back," the left-hander said.
Man of the Match Makhaya Ntini, who had match figures of 8-89, complimented the other seamers for supporting him well. "Andre Nel always keeps up the pressure. Now we go to Cape Town, which is one of our hunting grounds," he said.