Du Plesis struck 134 and De Villiers 103 as South Africa fell eight runs short of victory and India three wickets. (Agencies)
"Credit to India, they played extremely well in the first four days. We showed a lot of mental strength not to fade away. I thought Faf and AB's knocks would go down as the best in all time," said Smith.
"We've played some high class Test cricket and things are even-stevens now. Those who've played the game would appreciate what an incredible innings that was from Faf and AB,” Smith added.
"Because when wickets are lost they lose in clumps. They took it down to the last hour and it was incredible. Unnecessary pressure on Faf going into the game and he's answered them all. There's good respect in the squad and to come out and bat and four and produce a performance like that was outstanding," Smith said.
Smith, who scored 44, admitted that his and Du Plesis's run outs were unfortunate.
"The run out was unfortunate, the win would have been incredible, but we've still done very well to take it this far. You have to be level headed and there is always another coming up and as test team we've done that well in the last few years and make sure we never lose the game," said Smith.
Smith was all praises for fast bowler Vernon Philander, who contributed with both bat and ball.
"Pushing into all-rounder category is Philander and he's been great for us so far. Morne's injury also played a part in making the decision to draw the game because he was not a 100 percent and he doesn't control that long body even when he was fit," he said.
Du Plessis said he overcame cramps to score the century.
"If you had asked us this morning that we would have saved the game we would have taken it. I was struggling a bit with cramps and some stomach aches too, which I don't normally get. I was thinking about Adelaide. I knew I had done it before and I just placed a very high price on my wicket and made sure the Indians found it difficult to get me. The wicket was just a blur. In hindsight, I should have been out there holding one end while Vern went took it on," Du Plessis said.
He also praised the Indian bowlers.
"India bowled very skillfully. Obviously they bowl in difficult conditions at home so if there is anything in the pitch they find it. They swing it both ways and it was a real test batting out there. We take it as a moral victory here and will look to build on this momentum in Durban," he said.
Du Plesis struck 134 and De Villiers 103 as South Africa fell eight runs short of victory and India three wickets.