It started from the very first delivery of the day. Jasprit Bumrah saw it skitter through at shin height and bounce before it reached the wicketkeeper.
In a way, that helped India. Their pre-match suspicions about Kanpur having low bounce were confirmed and their slip cordon was a lot more confident with the positions they'd chosen, really close in to the bat. Bangladesh's first wicket fell because Yashasvi Jaiswal was only 14 metres away at gully.
Bumrah puts a lot of effort behind the ball. His action is only one small part of why he is so hard to face. The rest of it comes from the snap of his wrist, which helps him dig the seam into the pitch and extract every bit of help that's there, whether it's movement or bounce. The fact that he did all that and the ball still barely rose up off the surface set the tone for the rest of his day.
Usually, it's great being Jasprit Bumrah. Just this once, it wasn't.
He bowled three straight maidens to start his spell, with Zakir Hasan hopping about, unsure of which of his edges were in danger. He also allowed 17 leaves in his nine overs. He was a little up and down. And yet, the genius that he is, he still produced 22 false shots (that's a ratio of one every three balls) and beat the bat thrice (6) as often as any other bowler.
Eventually, even the good work that he was doing brought Bumrah a little bit of frustration - because this time unlike many others - he was really trying to get wickets instead of what he usually does which is settle on a length and slowly prey on the batter's technique. He kept shifting from over the wicket to around and back again, like a go-between trying to patch up a lover's quarrel. He had to experiment like this because the softness of the pitch had given Bangladesh a margin of error. On a harder surface, the ball might have gone through quicker and carried through higher and made him more of a threat. On this one, the batters seemed to have an extra second to adjust to all the sideways movement he were getting.
India, though, had a deep enough bowling attack and together they kept Bangladesh under enough pressure that at the end of a truncated day's play, they were still in control of the game. Their decision at the toss to bowl first - a first such instance in a home Test since 2015 - was built on the basis that the three-man pace attack would be able to exploit the overcast conditions. And it can be no bad thing that their fast bowlers are getting as much of a workout as they are in a home season that is leading into a huge away tour of Australia.
If Shami is fit, India might just go in with their strongest pace bowling attack in Australia later this year.
Akash Deep's performances, not just his wickets, but the way he seems to be getting them in his first spell, are a good sign. If he keeps this up, one of the problems that affect India when they travel - the support bowlers following the lead bowlers and releasing the pressure - may not have too much of a say on the final scorecard.
For now, the attention remains on Kanpur. Its weather will keep India's fast bowlers front and centre and Bumrah will be back on day two - so long as the rain stays away - producing more magic balls. Everybody walked off to the dressing room on the back of one, actually, and as he saw it nip past, instead of taking the outside edge, Bumrah threw his head back and half smiled. Usually, it's great being him. Just this once, it wasn't.