Dean Elgar and Quinton de Kock hit hundreds, but R Ashwin five-for keeps India in front

Stumps South Africa 385 for 8 (Elgar 160, de Kock 111, du Plessis 55, Ashwin 5-128) trail India 502 for 7 dec. (Agarwal, 215, Rohit 176, Maharaj 3-189) by 117 runs

South Africa exorcised some of the demons from their last tour of India on a day of glorious batting in which two of their players scored hundreds. So tough is it to play in India that despite doing much better than expected, South Africa were looking at the prospects of having to bat out three-and-a-half sessions to save the Test, which is roughly what they had batted in this innings.

Thanks to R Ashwin's 27th five-for, Dean Elgar and Quinton de Kock will have to put off full-fledged celebrations of their incredible hundreds by two days. India still led by 117 runs with two South African wickets standing. Should the last two wickets fall early, India have enough cushion to be able to time their declaration in the third innings.

Yet the magnitude of South Africa's achievement cannot be understated. They were 15 short of becoming the first visiting team since 2013 to score 400 when not batting first in India. That year was the start of India's dominant run at home since when they have lost just one home Test and only weather has been able to deny them a win at home when they have won the toss.

Bringing the biggest fight to the Indian juggernaut were Elgar of the "this is not Jo'burg" fame from the last tour and de Kock, who was not considered good enough by the South Africa selectors the last time around. The originator of that Jo'burg jibe, Ashwin, had to work much harder for his wickets here, but he showed he had just enough in his repertoire to come out with his head held high on a tough day.

Elgar's 160 was 18 short of the highest score by a visiting batsman in India's latest dominant run at home, de Kock's 111 was a wonderful display of natural talent backed by a clear head. It was hard work for India's spinners on a pitch that might not have been as flat as Rajkot against England or Delhi against Sri Lanka but didn't quite break up like Indian pitches do of late. That shouldn't take credit away from South Africa who were ruthless against any marginal error in length, especially on the fuller side.

For long periods of the innings, South Africa's was the second-fastest innings of 80 overs or longer by an away team in India in this dominant post 2013 era. Elgar, de Kock and Faf du Plessis, who nearly matched his 2015 series tally of 60 runs in one innings, hit 42 fours and seven sixes between them. That's 64.4% of their runs in boundaries.

The most striking method, though, was Elgar's, who had to fight through a top-order collapse on the first evening and saw Temba Bavuma go early on the third morning. During the last South Africa tour of India, Ashwin had mocked Elgar by saying in a press conference that this is not Johannesburg with regards to his dismissal trying to hit offspin against the turn. In this innings, though, Elgar, who called the pitches on the last tour a farce, kept playing Ashwin against the turn. Thirty-six of Elgar's runs against Ashwin came through the leg side, including the slog sweep to bring up the century. Ashwin showed he was a good sport by applauding the innings even before the ball had landed beyond the midwicket boundary.

In the four years since that last tour, South African cricket has seen a lot of turmoil, but Elgar has been a picture of stability. He has been their best batsman these four years, and that has not happened without a method. His method against spin here was to defend solidly, but every once in a while - like a swimmer coming up for a breath - he hit a boundary to earn himself the breathing space that India's cauldron-like conditions deny you. Sixty-three of his 160 runs came through lofted shots, the highest rate for any batsman in this Test. Rohit Sharma, known for his lofted hits, was just behind.

Elgar's stability allowed du Plessis to get into an attacking mindset, employing the sweep shot to good effect. India's bowling seemed unremarkable in this period, but they were not allowed to bowl well. Calculated risks were taken to put them off their rhythms. One of the biggest changes from the second evening was that Ashwin was now bowling a more defensive, straighter line. However, for Ashwin it has always been about getting the drift to bowl it wide outside off and not just spearing it in there. When he got one to drift away from du Plessis, the South Africa captain was now playing at a ball outside the line of his head, and it turned back to take an inside catch for backward short leg to hold.

At 178 for 5, South Africa still needed to do a lot of work. The ball had gone soft, the pitch was not turning from the straight, and India strived to save their spinners for the second new ball. De Kock, who had started attacking at any rate, was not going to let part-timers and a seemingly less-than-100% Mohammed Shami get away with quiet overs. Some clean hitting followed in a second successive stand of 100 or more. De Kock, too, brought up his hundred with a six off Ashwin.

Just before that, Elgar made a fatal misjudgement of length, top-edging a sweep for Jadeja to become the fastest left-arm bowler to 200 wickets. The new ball had more bite than the old one, and Virat Kohli was now asking his star spinners to do something for him. Ashwin did just that with two ripping offbreaks followed by one that didn't turn and consumed de Kock. He completed his five-for with a loopy wide offbreak to draw an expansive drive from Vernon Philander and bowl him through the gate. With just four overs left in the day, South Africa would have expected better from a veteran who played this Test partly because of his batting.

Those wickets in the extra half hour to make up for the rain on the first day had set up a thrilling finale to this Test. Provided there was no more rain.