The last time India played a Test series in South Africa, they made an extraordinary start. Within 29 balls of the first morning in Cape Town, South Africa were 12 for 3, with Bhuvneshwar Kumar running rampant.
At the time, Virat Kohli had been India's full-time Test captain for three years. His team had dominated every opposition at home and claimed resounding series wins in Sri Lanka and the West Indies. They were now beginning a cycle of tours that would test their skills, their adaptability, and their ambitions to the limit, and they had made one hell of a first impression.
Over the rest of that day, however, Bhuvneshwar, Mohammed Shami and the debutant Jasprit Bumrah demonstrated not just their obvious skill but also a sense of naivety, erring frequently in length and line in their over-eagerness for wickets, and 12 for 3 eventually turned into 286, a winning first-innings total on a Newlands surface that seamed from start to finish.
That chaotic energy pervaded the rest of that South Africa tour, and the tour of England that followed. India won Tests in Johannesburg and Nottingham, but they lost the other six, often from promising or even dominant positions. Their bowlers were world-class, but so too were those of South Africa and England, whose familiarity with home conditions often translated into better control over longer periods.
****
To see just how far India have come since then, watch this video. It's the highlights of the final day of India's most recent away Test, at The Oval in September. It's 15 minutes and 39 seconds long, and India are wicketless for the first two minutes and 48 seconds. Nothing spectacular happens in that period, but that's kind of the point.
Instead of the wickets and pulls and cover drives that would normally feature in a highlights package, we see this: India are bowling stump-to-stump lines with strong leg-side fields, and they occasionally drift too straight and concede a single or, on a couple of occasions, a boundary off a leg glance. There's one off-side boundary too, off a defensive shot that's edged through a gap in the slip cordon.
Those two minutes and 48 seconds of non-highlights came from a passage of play in which India conceded 19 runs in 8.3 overs to two set batters - England began the day at 77 for 0 - in good batting conditions. They were waiting for an opening, trusting that it would come, and making every effort to ensure that they relinquished none of their control over the match by the time it came.
In place of the chaotic energy of early 2018, India radiated a sense of knowing calm.
****
Between the South Africa tour of 2017-18 and the one they've just begun, this is the biggest leap India have made as a Test team. It's a product of their painstaking preparation - two ready examples being Ravi Shastri and Bharat Arun devising a 21st century version of leg theory five months before their 2020-21 tour of Australia, and R Ashwin making Steven Smith his "obsession for about six months" - but also of their bowlers' ability to execute plans.
The Shami of 2021, for instance, is a vastly different bowler to the Shami of early 2018. He has the same skiddy pace and flawless wrist position, but he's fitter and bowls with a better-grooved action, and is therefore less likely to stray in line or length by accident; through experience and success he has also grown more patient and trusting in his own methods, and is less likely to stray by design.
India's attack has greater depth too, which has allowed them to rest their senior fast bowlers whenever possible, and to play four quicks as and when required, without a massive drop in quality between the new-ball bowlers and the second change.
As with any tour, though, this one begins with challenges. The absence of Ravindra Jadeja will test India's ability to play five bowlers; it remains to be seen if they trust the lower-order ability of Ashwin and Shardul Thakur enough to do so. If they don't, they will need to find ways to manage the workload of four bowlers without compromising on the pressure applied on South Africa's batters.
The batting unit, meanwhile, is without Rohit Sharma, its form player of 2021. And where Kohli, Cheteshwar Pujara and Ajinkya Rahane were all 29 and in their theoretical prime during the 2017-18 tour, they are now 33 and with averages in the 20s and one century between them in the last two years.
A new coaching group is in place too, and Rahul Dravid and Paras Mhambrey are yet to establish the relationships with the players that Shastri and Arun built over their tenure. The captain is now captain in only one format, and his relationship with his cricket board is at the rockiest it's ever been.
But a Test series is, at its heart, the contest between two bowling attacks, and South Africa are yet to complete the transition away from Vernon Philander, Dale Steyn and Morne Morkel. They have also lost Anrich Nortje to a hip injury. Kagiso Rabada, Lungi Ngidi and Duanne Olivier - which seems the likeliest combination to play on Boxing Day - could still prove formidable in home conditions, of course, but measure that against the attack that started South Africa's last home series against India: Philander, Steyn, Morkel, Rabada.
India, meanwhile, have a bowling attack with skill and variety, and the know-how that has come from playing and winning Tests in nearly every part of the world. That, then, could be their biggest reason to believe they have their best-ever chance of winning a Test series in South Africa.