It wasn't dismissing Kumar Sangakkara twice in his debut Test, though that was pretty good. Or the five-fer at the MCG, though that was also pretty good. Not the swooping outswinger that did for Mitchell Johnson at Headingley, though it's difficult to better that aesthetically. It wasn't even the eight-ball spell in which he took four middle-order wickets against England at Lord's, that euphoric high before the juddering comedown.
None of it, not the swing, the pace, the youthfulness, the hair, any of it. No, what now feels most instructive from the early Mohammad Amir canon is the first over of the T20 World Cup final in 2009. You know this story. Lord's. Firestarter Dilshan. Shahzaib round the corner. Ian Bishop, booming, calling it. Delirium in the stands, all over. Next month, as the ninth T20 World Cup enters its Super Eights, it'll be 15 years since that over; what turned out to be a window into Amir's past at that point and a glimpse into his future.
Unsurprisingly for how important the over was - and that it's Amir, a bowling nerd - he remembers it in some detail, the most telling of which is that, aged 17, six games and two weeks into his senior Pakistan career, it was he who hatched the plan.
"I had watched Dilshan bat through the tournament and I figured he was hitting the Dilscoop whenever he was getting stuck in an innings," Amir says. "You know how a bowler has a stock ball? This was his stock shot. When he gets stuck, he plays that shot. It was his release, his get-out shot. To stop it I thought, why not put him on the back foot?"
Amir had first-hand knowledge of the shot, having been Dilscooped in Sri Lanka's group-stage win over Pakistan earlier, also at Lord's early on. So the day before the final, he went to the captain, Younis Khan, in the bowlers' meeting and presented his plan. Bowl bouncers, hit the shorter side of back of a length, give him no room, no space. Younis had watched Amir's development closely through the preceding domestic season, including being dismissed twice by him, and was happy to let the kid take the lead.
Now a short-ball plan is hardly rocket science, least of all in today's T20s, war-gamed as they often are right down to the last percentage point of intent in a batter's shot. But to be 17, in your first major assignment, a world event, and this attentive to detail spoke of the preternatural abilities of young Amir; he had game sense in a way cricketers that age usually don't.
In any case, the greatness of the over lies in its near-perfect execution, beginning with a bouncer first ball. Angled across Dilshan, nearly 88mph, whizzing past his right ear and just over his right shoulder. The bouncer can be as difficult to get right first up as the inswinging yorker is. Too short or too much effort - on a bouncy track as Lord's was that day - and it can sail over for wides. Not quick enough or the wrong line and it becomes a gimme. But if done right, then, without even taking a wicket, it makes an impact.
"Most batsmen won't think that in the first over, the first or even second ball he'll bowl me a bouncer," Amir says. "If you show that aggression and in a big game, it puts the batsman under some pressure. His plan has to change and you're now one step ahead."
Shahid Afridi, another big influence in Amir's first year, hared up to him after that ball. '"Charr ke bowling karo, no fear." (Get right on top of him.) And the next two balls, Amir did, both sharp, around 88-89mph. But speed wasn't the thing. Each rose from back of a length to near-about the height of Dilshan's armpits - charr ke - angling across but not enough to afford him any room and no length to drive. In other words the balls played him rather than the other way round; both dots, Dilshan now growing fidgety. Bishop razor-sharp on air: "Another short ball, three short balls in a row, definite plan we're seeing here."
Then, another bouncer, except, this time, a slower one. Dilshan was about a month early on the shot. "He got through the pull, and it almost went to [Kamran] Akmal off the back of his bat. That was the plan, that when you're attacking a batter and trying to get him out, you try to puzzle him. You have to get him out. You can't let him settle on one pace. I had bowled three dots to him. If I bowl him a cutter, Dilshan was the kind of batter who wouldn't sit back after three dots. His natural game was to dominate. He pulled hard but didn't connect."
By this stage, four balls in, besides the inherent challenge of a left-arm angle, Dilshan had already dealt with sharp bounce, nearly 90mph pace, subtle variations in length, a 10mph-drop in pace, and before the slower bouncer, a field change in which square leg moved to short fine and deep fine leg to deep square. Puzzled, as Amir says, and now, with the field switch, a temptation dangled: the get-out shot, the Dilscoop is on.
The ice-cold precision with which the over had been executed thus far belied the nerves Amir had been feeling before the start. Younis had given him a coping mechanism a couple of weeks earlier when he had started for Pakistan in the pre-tournament warm-up game against India at The Oval. Though it was a warm-up, it was Amir's first time playing for the senior Pakistan side.
"That game felt like it was an international, with a live telecast and the crowds," he remembers. "I was really nervous, bowling the second or third over, and Younis bhai came to me from mid-off. He said, take three deep, long breaths. Then, imagine you're playing for National Bank [Amir's domestic side that season]. Bowl like you did for them, like this is a domestic game. 'Khul ke bowling karo.' [Bowl without fear.] When the captain tells you something like that, half the tension is gone."
Deep breaths and then the big exhale. With his fifth ball, Amir went ever so slightly fuller - the ball bouncing to waist-height rather than chest - and across him, outside off again. Instead of trying to slap him through point or extra cover, shots that Dilshan played well, he couldn't resist the scoop. He was in a situation and he need a get-out. Recognising that neither line nor length were his friends here, he transitioned to an attempted pull but ended up top-edging limply to short fine leg, Shahzaib Hasan's most vital contribution to Pakistan, a smart catch over his shoulder. The tournament's leading run-scorer, the player of the tournament, the third-highest strike rate among the top ten scorers, gone for a five-ball duck. It wasn't the game - Afridi would later become its boss - but it was the first critical blow.
Even though he was only a teenager, the cutthroat world of this little battle - take the batter down before they take you down - was one Amir would have been familiar with. His first, informal, trial as a pre-teen, had been to prevent a tape-ball legend from hitting him for more than two boundaries in an over. That one over (he conceded one boundary), bowled in slippers and shalwar kameez got him into a big tape-ball tournament that evening, where he was spotted by a scout and whisked away to an academy in Rawalpindi and thus unto the world.
And ultimately, after a long and convoluted interregnum he has found a way back to that ruthless world: no longer the bespoke bowler dreamt out of bright blue skies but a mass-produced unit from a sky the shade of concrete. That's not meant as a slight so much as to assert that there is little romanticism around this Mohammad Amir. He is now a pure T20 bowler, traipsing around the world doing what he was doing the day he was spotted; a pared-back run-denier who has sharpened all the senses and tools he had at his disposal as that child, and simply shed all other baggage.
Before his return for the series against New Zealand in April, he had not played for Pakistan in nearly four years, after a tawdry falling out with management. Whether he should be back, ahead of younger options such as Zaman Khan and Mohammad Wasim Jr, is a valid question. To which, of course, there is no definitive answer.
At 32, perhaps no, he shouldn't be. As the second-highest wicket-taker over the last two seasons in the CPL, ahead of an ICC event in the Caribbean, perhaps he should be. As a bowler with an economy of 6.30 in the powerplay and 9.26 at the death in all T20s since September 2019 - placing him seventh and ninth among all pace bowlers (at least 600 balls and 300 balls bowled respectively in those phases) - there is a case. In a squad with Shaheen Afridi and Naseem Shah, certain starters and expert in those phases, with Haris Rauf's pace, backed up by the emergent Abbas Afridi, there is less of a case. Another left-arm pace option, on the other hand, is no bad thing.
What is clear is how much T20 has changed since he bowled that over. Boundary sizes in that final were short square (60m and 64m) but much bigger in the other directions - ranging from 75m to 85m - than is common today. Pitches and balls, at least according to Amir, were not as unresponsive as they are now. Above all, to fixate on one single shot as Pakistan did on the Dilscoop as a threat is so… naïve. The scoop now, like a solid defensive in long-form batting, is merely the base off which 360-degree batting is built.
"Now, from the first ball the batsman is playing scoops," Amir says. "Your variations have to be so strong now. With the new ball you have to hit that right area and it's only for an over, no more than that. After that, your basics, especially your variations, have to be strong. The batsman cannot predict what you are bowling. If he does, then 10-12 off an over is easy.
"Every single ball you have to be on. Your variations, but especially your executions of it. That is where you have to really work hard as a bowler, to execute these days. You can bowl a slower ball or a yorker, and if you don't get it right, then even half-hits are gone for six. The execution has to be 100% right."
Perhaps this is what Pakistan want from Amir, this broad sweep of experience and perspective, the pragmatic foil to the dreaminess of Naseem and Shaheen; we're talking 15 years' experience as well as winning hands in two ICC titles. Modern Pakistani fast-bowling careers don't come as robust as this (which is saying something given the interruptions of Amir's career). Then again, this is Pakistan selection, so it's probably nothing of the sort. They've likely just panicked, lost faith in younger bowlers just when Amir has hit a decent run of form to impress men who he has, after all, played with.
Maybe they're hoping that the kid who was once wise beyond his years, is wiser still after all these years.