In the 188th over of India's innings, Ravindra Jadeja cut Moeen Ali slightly wide of deep point. Karun Nair had batted the whole day in the Chennai heat and humidity with all his armour on. He had added 223 to his overnight 71 in close to six hours on his second day of batting. He had run 146 of his 294 runs until then. He was visibly struggling running his runs, walking some of them. On some occasions he sprinted for the first, but would stop dead as soon as he realised the second was not available. Towels, gloves and fluids were being sent out.
When Jadeja hit that ball into the gap, Nair ran just as hard for Jadeja's runs as he did for his own, and initiated the second, and somehow stumbled into his crease. The declaration was perhaps delayed because of his proximity to the landmark, but Nair was not making any distinction between his runs and the team's.
About nine overs earlier, during the drinks break, the big screen at the ground began to show the highlights of Virender Sehwag's triple-century at the same venue eight years ago. The similarities were unmistakable: weather-affected Test, consequently a flat pitch, big score by the visiting team after winning the toss, and then a triple-century in response. You could see Nair was watching it even as Ben Stokes ran in. You wondered if that was when the thought struck him. Or if that was when he started feeling he was on to something beyond just special: a debut hundred turned into a triple-century. Like Sehwag, he could become now the fifth man to bring up his hundred, double-hundred and triple-hundred all on the same day.
Nair, though, is a level-headed man. He didn't let such thoughts get into his head. If they did, he got rid of them quickly. "I think it never took place in my mind," Nair said of the thought of scoring the triple. "After I crossed 250, the team management had certain plans of going after the bowling and declaring. So I think within the space of five overs I got to 280-285, that's when I started thinking and Jaddu [Jadeja] kept egging me on to not throw it away and get to 300 easily."
Like KL Rahul and Virat Kohli, Nair too didn't visibly have to change gears although his pace went up dramatically. The three hundreds came off 185, 121 and 75 balls. The last fifty took just 33 deliveries. Yet, apart from the flat-bat pull over mid-on, you couldn't pick a shot a traditional Test fan should scoff at.
"I think after reaching hundred the pressure is off," Nair said. "You just go out there and play the shots that you can and you just look to hit the gaps. Once you cross 150, it is just playing freely like how you always do and just expressing yourself.
"My game doesn't change much. It's just the mental approach that changes. In Test matches, obviously you have a lot more time to get settled and play big. I think the approach doesn't change at all. I don't play any different shots in any other format. I just play the same way."
It helped that Nair swept and reverse-swept the England spinners to distraction. Fifty-three of his runs - out of 195 against spin - came through the various varieties of the sweep. "I have played the sweep shot almost all my life," Nair said. "You do have to practice a lot. You have to work hard at it. It is my go-to shot whenever I need some boundaries. If the gaps are open for it, I go for it."
Like his India A and Rajasthan Royals coach, and a great from his state of Karnataka, Rahul Dravid, Nair internalises his emotions. With his parents watching - his mother for the first time because she feared she was an unlucky charm - this would have been quite an emotional moment for him. Yet what you saw was arguably the most subdued celebrations on reaching a triple-hundred.
"There are a lot of things that go in my head that I want to do, but at that moment it just doesn't come out," Nair said. "I think I will just have to get more hundreds for me to show emotion."
Until then where does he show emotion? "There is always the shower to do all these things."