It feels oddly startling now - viewed against Rahul's overall Test numbers, which speak of nothing but unfulfilled potential - but six years ago, when Australia last toured India for a Test series, it was the kind of fact you might have expected to read about Rahul in six years' time.
In that 2016-17 Border-Gavaskar series, played on four distinctly different pitches, three of them hugely challenging, Rahul faced the best and most balanced visiting attack to bowl in India in the last decade. He scored 64, 10, 90, 51, 67, 60 and 51*, and finished the series as its third-highest run-getter behind Steven Smith and Cheteshwar Pujara. Those scores were part of a stretch in which he passed 50 ten times in 14 innings.
Rahul turned 25 during that purple patch. He had already scored hundreds for India in all three formats, and it felt like he could do, well, anything.
Six years on, he's done, not everything, but every manner of thing you can do as a batter at the highest levels of the game. He's scored a 14-ball half-century in the IPL, and he once took 108 balls to hit his first boundary while laying the platform for a Test hundred at Lord's. He can flick balls off his hips for massive, effortless sixes, and he can leave fourth-stump outswingers by withdrawing his bat from the line of the ball at the last possible instant.
Rahul can do anything, but he's also, perhaps, a victim of that range of skills. It's part of a cricketer's job now to adapt to multiple formats, but the challenge is perhaps trickiest for those that are most versatile. Virat Kohli bats in an entirely different way in Tests than he does in T20s - the two formats are, in truth, entirely different sports - but the difference is smaller than the difference between how Rahul bats in Tests and how he used to bat in T20s back in, say, 2018, when he had an IPL strike rate of 158.41.
While there were other contributing factors as well, the difficulty of switching from that furious T20 tempo to red-ball mode probably had something to do with Rahul enduring a miserable 2018 in Test cricket: 12 Tests brought him just 468 runs at an average of 22.28. It wasn't just that he made a string of low scores, but that his technique seemed to have fallen apart, leaving him vulnerable to being beaten on both edges of his bat.
When Australia visited these parts six years ago, India had a future superstar in their ranks, and he happened to be a tall, languid top-order batter who timed the ball like a dream. Everything is different now, and everything is just the same.
Likewise, it may not have been entirely coincidental that Rahul's successful return to Test cricket in 2021 - a year in which he scored hundreds at Lord's and Centurion that were masterclasses in leaving the ball - came after he changed his T20 game drastically, severely limiting the risks he took in the early parts of his innings. It earned him criticism from all quarters, including this one, but you can't please everyone if you're trying to make the best of juggling three formats with entirely different demands.
Rahul's Test comeback began one of Indian cricket's great rollercoaster rides. From not even being part of the first-choice Test XI at the start of 2021, he found himself captaining India in their first Test of 2022, when both Kohli, their Test captain at that point, and Rohit Sharma, his deputy, were out injured. He also captained India in two Tests in Bangladesh at the end of 2022, when Rohit, now the all-format captain, missed the tour with another injury.
But just as Rahul reached his highest point as an Indian cricketer, in terms of stature, his form fell away completely. He averaged 17.12 across eight innings in 2022, and got to fifty just once.
Four Tests and eight innings aren't much of a sample size at all, of course, but Indian batters don't always have the luxury of large sample sizes. This is particularly true right now, on the eve of a four-Test home series against Australia, when India are almost certain to play only five specialist batters, and when competition for those five spots is extreme.
If Shreyas Iyer had been fit to start the first Test in Nagpur, it's quite conceivable that Rahul would have had to sit out, immediately after captaining India in their last Test. Iyer, whose counterattacking game against spin has been crucial in India's recent games in the subcontinent, was a near-certain starter in the middle order, which would have meant that Shubman Gill would have had to open the batting if India wanted to play him. And given how Gill has been batting lately - even if those runs have come in white-ball cricket - India would find it extremely difficult to not play him.
As things stand, Iyer has a troublesome back, which means Gill is likely to bat in the middle order and Rahul will keep his place at the top. If conditions in Nagpur are ripe for a low-scoring, spin-dominated shootout, however, there's a chance India could be tempted to gamble on a game-changing cameo or two from Suryakumar Yadav, which would leave room for only one of Rahul or Gill.
Rahul vs Gill. It might only be a hypothetical question for now, but there's a certain poignancy to it. When Australia visited these parts six years ago, India had a future superstar in their ranks, and he happened to be a tall, languid top-order batter who timed the ball like a dream. Everything is different now, and everything is just the same.