Look through this website's list of the 20 balls of this century, and ask yourself this: how many of them did exactly what the bowler had planned at the top of his mark?
Most are simply a happy confluence of delivering the ball with a great degree of physical and technical skill - perfect wrist and seam positions, or high RPMs along the perfect axis - onto a good area, getting a little bit (or a lot) of help from the pitch, and maybe the batter not quite being up to dealing with what happened next.
And that's no slight on those balls or the bowlers who delivered them. Test cricket is mostly about hitting good lines and lengths over and over again, doing so at high pace or while giving the ball a big rip, and hoping that the excellence of the process will bring about good outcomes.
Sometimes, though, a magic ball is really a conjuror's trick. Jasprit Bumrah to Shaun Marsh, for example. A moment of genius almost entirely orchestrated by the bowler.
He has only played 25 Tests, but Bumrah has already built up a collection of these moments. There was Keaton Jennings in Southampton, wrung completely out of shape by what seemed to be the world's first sighting of a new weapon - Bumrah's inswinger to the left-hander. There was Ollie Robinson at Lord's, feet cemented in place with a series of short balls, and back pad thudded into with a slower offcutter from around the wicket.
And then, on Wednesday, as day four of the Centurion Test drew towards an exhausted close in fluctuating light, Bumrah delivered two in the space of 14 balls. First, a perfectly good leave from Rassie van der Dussen rendered not-so-good by wicked break-back exaggerating the angle from wide of the crease. A beaming Bumrah clapped his hands as he ran towards his team-mates, a thing he does when he is especially pleased with himself. You probably did the same thing at the same time.
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Bumrah didn't clap after delivering what turned out to be the last ball of the day, a searing yorker that nightwatchman Keshav Maharaj had no answer to. He turned around instead, and stared at the non-striker Dean Elgar, who had said something to Bumrah earlier in the over when Maharaj had punched him off the back foot through the covers.
Before Bumrah's late burst, India had spent 103 frustrating minutes attempting to break a stubborn third-wicket partnership between van der Dussen and Elgar, throwing everything at the pair, often getting the ball to deviate sharply or confound the batters with steep or low bounce, but not quite managing to create that one chance.
With rain expected on day five, there may have been a sense of anxiety among India's players. Bumrah had blown it all away.
As much as he is a bowler of great balls, Bumrah is a great bowler too. A supremely persistent hitter of good lines and lengths, who happens to hit those areas harder, and at greater pace, and with more backspin on the ball than most.
His one wicket on day five was a triumph of this sort of persistence, though it contained a brand of magic of its own.
Bumrah had harried Elgar all morning, mostly testing his outside edge and on one occasion getting him to edge thickly between second slip and gully. But as is often the case, making Elgar look uncomfortable and dismissing him were proving to be entirely different things. He had survived the first 9.5 overs of the day alongside Temba Bavuma, and moved to 77 in the process.
The sky over Centurion was clear, but rain was still forecast for the afternoon. Elgar had already been reprieved once in the morning, Mohammed Shami dropping him off his own bowling.
Then Bumrah, delivering from around the wicket, got one to veer sharply towards the stumps. Elgar, having been made to worry constantly about balls in the corridor outside off stump, found himself in the wrong position, head well outside the line. The ball kept a touch low too, and Elgar, hopping across his stumps and playing all around the ball, was struck on the front pad, right in front.
Was this movement in the air, or off the deck? It turned out to have been both. Bumrah was probably looking for the inswinger, but the seam came out of his hand ever so slightly wobbly. Then the ball seemed to hit a crack and deviate, and as it did so, the seam emerged miraculously unscrambled, canted towards fine leg, with the ball's rough side facing the leg side.
There wasn't a whole lot of distance between where the ball pitched and where it hit Elgar's pad, but the ball swung inwards over that brief duration, ensuring Elgar was in no danger of inside-edging it.
Not an intended bit of magic, but a reward from the cricketing gods.