Johannesburg and Delhi are important signposts on R Ashwin's journey as a Test bowler. On December 22, 2013, Ashwin went wicketless for 36 overs as India tried to bowl South Africa out in four-and-a-half sessions for what could have been one of India's greatest Test wins. He was dropped from the side after that for six Tests, and then when India went to Australia, he was not picked for the first Test of the series. Ashwin was hurt, but he went into the nets and during that Adelaide Test, he says, something clicked in his action, which has changed him as a bowler.

Ashwin felt staying out for so long was a little harsh, but it was not as if he was letting himself take it easy this time. Six years ago, in Delhi, at the Palam Ground, about 20km from Feroz Shah Kotla where he capped off a fantastic series on Monday, Ashwin had had his domestic Johannesburg moment. It was the quarter-final of the Ranji trophy in 2009-10, and Tamil Nadu had scored 463 in the first innings. The onus was on Ashwin to get Tamil Nadu the first-innings lead, but a Delhi side full of domestic stalwarts crawled its way to a lead and into the semi-final. Ashwin bowled 62 overs for 116 runs and picked up just two wickets. He says he took the easy route back then, and consoled himself saying the pitch was completely flat. That did not repeat in Johannesburg.

For a final icing on this cake, Ashwin had to come back to Delhi. He was already on his way to being the Man of the Series, but he had hardly been challenged in the first three Tests of this series. Now he was up against a pitch going slower and lower by the minute and stalwarts who were hanging on for dear life. Hashim Amla, AB de Villiers and Faf du Plessis - masters of such blockathons earlier too - were leading this effort where no bat would be raised in anger, where the bowlers would be given no chances by way of poor shots, because there would be no shots.

India had enough time, you would think, but the way South Africa went about their job, something special was needed with the ball. It was the perfect time for Ashwin to find some redemption from memories of those two matches. It had generally been a difficult week for Ashwin with his home city Chennai flooded, and his parents out of communication channels. While Ashwin batted in the first innings, his wife tweeted they had not heard from Ashwin's parents in more than a day.

And here there was a Test to be won. And what a test it was for the Indian bowlers. The first wicket had come easy, but when Amla and Temba Bavuma dead-batted everything, you knew it would need something extraordinary from somewhere to get a wicket. The man who came closest was Ashwin, nearly getting Amla with a legbreak. He followed it up with a perfectly pitched offbreak that did not turn as much as expected to get Bavuma out.

Then, Amla and de Villiers began to dead-bat. It seriously looked like they could score the runs drip by drip in four days if this were a timeless Test. Except that it was not. Time was running out for India. Not fast, but fast enough to possibly refresh the demons from Johannesburg and Wellington. Ashwin then bowled another legbreak. Bear in mind he is an offspinner. He has to show to the batsman he is bowling finger-spin, then change the grip at the last moment and land the delivery. This one to de Villiers drifted in and dipped late. Shane Warne would have been proud of it. It drew a false defensive shot from a batsman so intent at not making a mistake.

Twice Ashwin came close to doing the sort of thing that immortalises bowlers, but perhaps magic was not what was going to give India the win. There was more hard work in store. On the fifth day, after waiting for eight overs with the old ball, Ashwin and Ravindra Jadeja were back on for the hard toil. They kept bowling ball after ball in that zone. Ashwin kept changing the trajectory to possibly play around with the batsmen's shape as they defended everything, while Jadeja kept using the crease and variations in pace. Not much worked except for when Jadeja found just the right amount of turn so as to not miss Amla's off stump when it missed the edge.

Ashwin had to wait longer. He tried tricks. He went through the repertoire. Except for a wrong'un, he tired everything. He even tried running in funny, cutting across between the umpire and the stumps, the way some left-arm spinners do. Who knows, he might even have thought of bowling left-arm. Who knows, he might actually be really good at left-arm spin.

As important as it was to break through the resistance, it was also important to burst through a door left ajar. Jadeja did so for him with du Plessis' wicket, and Ashwin now knew he could get Duminy. He spread the field for de Villiers, who might have made the mistake of letting Ashwin bowl to Duminy. It took Ashwin six balls to set him up with offbreaks before trapping him lbw.

When he got de Villiers - 297 deliveries for just 43 runs later - with his first ball after tea, Ashwin had sealed his status as the biggest impact man in the series. Almost invariably, he struck when South Africa embarked on something new: innings, day and session. Thanks to Ashwin, those awkward minutes when a team starts an innings minutes before an interval became torturous. In Mohali, he struck in the evening, in Nagpur he did so twice, in his first over in Bangalore, he broke what looked like a solid opening partnership. When made to work hard in Delhi, it was great to watch him find a way.