Rehan Ahmed shows early signs of substance as England relive their fragile legspin dream

There were still 10 minutes left of the lunch break, but Rehan Ahmed was already out of the away dressing room of the Karachi National Stadium and back on the field. With senior spinner Jack Leach for company, he turned his arm over a few times, bouncing on the spot between deliveries into a mitt on the full.

The previous few hours had been equal parts historical and emotional. At 9.30am on Saturday, when the toss went up and the teams were confirmed, Ahmed officially became England's youngest male Test cricketer, having moments earlier been presented his cap by former captain Nasser Hussain, with his father, Naeem, by his side. He had barely started bending the stiff navy-blue peak before dad gave him a hug followed by a kiss. All that was missing from the "Asian dad embarrassing his teenager in front of their new friends" bingo was a squeeze of the cheeks.

Then, with 16 overs gone, Pakistan were 59 for 2 after choosing to bat first in this third Test, and Ahmed found himself with the ball in hand at the University Road End. On hand were a slip and a bat pad, though neither was especially in the game in his maiden spell: his five wicketless overs went for 37 runs, through him either being too short or too full. Against Babar Azam and Azhar Ali, two accomplished players of spin, there was never going to be much margin for error or goodwill towards an opponent making only his fourth appearance in all first-class cricket.

Was this a kid nervous on Test debut? Absolutely. He admitted he had not been able to eat or sleep on the night before his debut, as he wandered around the team's Movenpick Hotel twirling a ball in his hand. Just 24 hours prior to that, Ben Stokes had called Ahmed into his room where he and Brendon McCullum informed him of the selection.

Ahmed's emergence with time to spare before the second session, however, was as much due to anxiety as it was of someone keen to continue onto the next step. In the past 11 months alone. a stellar Under-19 World Cup, a first-class debut, a stint in the men's Hundred and now a Test cap have all come in such quick succession that he has been conditioned to always look ahead. As a self-diagnosed cricket badger, something he revealed earlier this year, he wanted to continue this realisation of all those hours spent behind closed doors, either shadow-batting or working out shadow batters. There is, with Ahmed, a good kind of restless energy.

By the time that second spell came around, those shoulders, joints and wrist were a little looser, and the cap was fitting a little better. The nerves had been shrugged off with the help of supportive team-mates and a captain who couldn't care less about the runs, and Ahmed truly got in amongst it from the Pavilion End. The googly many had raved about - too short in the morning - was on the money in the 42nd over. Ahmed, from around the wicket, flung himself over his front left leg to rip the ball past Saud Shakeel's outside edge. As a result, the left-hander played his next delivery a little wider than he would have liked. But this time it was the regulation leggie. With the inside half of his bat more exposed, a inside-edge cannoned off Shakeel's front pad and dropped into the sprawled, upturned right hand of Ollie Pope at short leg.

The comfort of that first wicket, reinforced by the swarm of team-mates offering their own elation at his maiden success all at once, liberated him into his freewheeling ways. And once that seminal five-over burst had come to an end - 1 for 19 - a change of ends back to his original starting point brought about the real spell of note.

Across 12 more overs - two before tea - he bedded in like this was all just a manifestation of those childhood moments to himself, when he had little but his own ambition and imagination to riff on. Indeed the wrong'un that brought his second wicket was the stuff dreams are made of. Another leftie hoodwinked - this time Faheem Ashraf - playing down leg, appropriately enough given where the ball landed, but left for dead as the delivery turned past his bat and into his back pad.

"I've been bowling at left-handers all my life," Ahmed beamed on Sky Sports at the end of play, once Leach had seen off the remaining Pakistan batters to wrap their innings up on 304. The left-hander in question? Older brother Raheem, who was in the stands watching alongside his dad. "I used the tactic I used against him: googly then legspinner. And it worked."

Legspin is hard, and doing it for England seems to make it even harder. Matt Parkinson debuted (as a concussion substitute) six months ago, Mason Crane five years ago and neither are likely to add to their single appearance.

Perhaps the hardest thing for both to cope with was the crash: the heights of the hype, followed by the ease with which both were deemed inadequate at this level. It is why Stokes, McCullum, director of cricket Rob Key and performance director Mo Bobat decided to keep the noise around Ahmed as quiet as possible. His progression from three County Championship games for Leicestershire into the Lions in the UAE, and then onto this Pakistan tour, was touted as a "soft launch" rather than the real deal. Ahmed was their exciting prospect they didn't want you getting too excited about. And now here we are, getting too excited about him.

Then again, the whole point of legspin - and the whole point of being young in a sport that no-one ever truly masters - is about being carried away by these moments, whether they happen to you or in front of you. To have both? Well, that's good fortune.

The late, great Shane Warne got excited when he first saw Ahmed in the nets at Lord's as a 13-year-old in 2017, when he dismissed Joe Root (lbw) and his current captain, Stokes (stumped). "I think you'll be playing first-class cricket by the age of 15," Warne said. In the end, he was only two years out.

Similarly, Pakistan head coach Saqlain Mushtaq was bursting with reflected pride, given that this debut had come in the birth country of Ahmed's parents. "It's a point of great pride that so many Pakistanis are playing for other countries," he said. "Rehan bowled very well today.

"The way he bowled certain deliveries to Babar and all of the Pakistan batters makes me think there's something about him. I see a bright future ahead for him. He plays for England, but his Pakistani roots make me very proud."

The talent is undeniable, the execution of tough skills exemplary under the most acute pressure he can have experienced so far. Of course, it is not on us to promise the world on Ahmed's behalf. And yet the compulsion to write a scale-tilting "but" here is just too strong. Especially so in this England team, where the current levels of optimism are such that nothing seems out of reach, not even the notion that they have a future Hall of Fame legspinner in their midst.

"I mean, I think it's the best-ever Test team that's ever played," said Ahmed, rolling with the theme of getting carried away. "To play at such a young age is just a blessing. I think you can't ... stuff like this doesn't come around like this, so it's great to make your debut at 18."

By the end of the day, with Ahmed having returned maiden Test innings figures of 2 for 89 in 22 overs, his father and brother had their heads down in their phones. There were congratulatory messages to respond to, and dismissals to watch on replay. Memories already cast in stone on day one of an international career that is just getting started.

Yes, English cricket has been burned many times over by promising more than it should, and that is not just limited to meeting legspinners more than halfway. With Ahmed, though, it feels like the right moves are being made for this latest tale to have a happier ending. The dressing-room Ahmed finds himself in will ensure he can tell his story in his own way, at his own pace.