Pakistan v England: Rehan Ahmed is the real deal - Jonathan Agnew
Rehan Ahmed's performance in taking 5-48 on the third day of England's final Test against Pakistan was remarkable.
He is 18 years old and in only his fourth first-class match. I know just how inexperienced and raw I felt after so few matches.
And yet, there he was, bowling England into a position from which they will surely win the series 3-0. In the process he became the youngest man to take a five-wicket haul on his Test debut.
It is very un-English to fast-track a player into Test cricket, but it was absolutely the right thing to do with Ahmed.
At 2-0 up, it was the perfect opportunity to see what the leg-spinner can do in conditions similar to those England will face in India next winter. They will have certainly learned more about in him in one Test than they would have done watching him play for Leicestershire next summer.
We wondered if Ahmed might be overawed by the occasion, but there was not a bit of it. In fact, he revealed himself to be a showman that revelled in playing on the biggest stage.
After Ahmed took two wickets in the Pakistan first innings, it was odd that captain Ben Stokes held him back until the 42nd over of the third day in Karachi.
gain, everything that Stokes touches turns to gold at the minute, and so it proved with Ahmed.
In a spell of 12.5 overs, Ahmed sparked a spectacular collapse and made himself the youngest leg-spinner to claim a five-wicket haul in a men's Test.
He will be the first to admit his first victim, Babar Azam, fell to a terrible delivery. It was a rank long-hop that Babar should have hit for six. Instead, the Pakistan captain hit it straight to Ollie Pope, whose hands must still be stinging after taking such a sharp catch.
what leg-spin can do. Even poor balls can be dangerous because of the natural variation in speed, bounce and skid. They can be hard to attack with a cross-bat. Yes, it was a lucky way to pick up a wicket, but Ahmed also bowls plenty of good balls that go unrewarded.
In contrast, his second wicket, that of Mohammad Rizwan, was near-perfect. There was lovely bounce and turn to take the outside edge, which is exactly what you want from a leg-spin bowler. 
From there, Ahmed was off and running and by the time he was walking off, showing the ball to the crowd, we all knew England had found someone special.
English cricket has long been fascinated by leg-spin, partly because of what Shane Warne regularly did to us in the Ashes.
England isn't the best place to produce leg-spinners - the conditions aren't particularly conducive to it. In the bid to find the next Warne, a few have been tried and discarded.
In Ahmed's case, he encountered the great man in the nets at Lord's, so for him to now put in a performance that Warne would have purred over completes that circle.
re is always something happening when a leg-spinner is bowling. They bring an energy and theatre to the game. They are the magicians, always looking to pull a rabbit out of the hat.
Part of Warne's act was to get the batsmen believing the ball was doing things it wasn't. I used to think of him as a pantomime dame.
Ahmed certainly has that aspect to his character, so in that sense has already mimicked the legendary Australian, even if he is clearly a long way off from matching his quality as a bowler.
It is now England's job to protect him, to make sure he doesn't get put in situations that will dent his confidence.
I don't think we will see him against Australia next summer - England will want the control offered by Jack Leach - but we can already pencil Ahmed in for the tour of India in early 2024.
Either way, it's absolutely fine for England fans to get excited about him. He looks like the real deal.
As for England, the idea of them coming to Pakistan and winning 3-0 would have been laughable after their defeats to Australia in Hobart or West Indies in Grenada earlier this year. No-one has ever done this to Pakistan because it is incredibly difficult.
Yet, here we are, with Pakistan the latest side left scratching their heads wondering if it is possible to stop the way England play. Yes, Pakistan have been below their best and missing a couple of key fast bowlers, but Stokes' side could only beat what was in front of them.
Now we will all be looking towards next summer, because the Ashes series against Australia is the one.
England will play the same way and the ruthless Australians will not take a backward step.
When England were hammered by Australia at the beginning of this year I was pondering the prospect of 2023 and came to the conclusion that England's proud unbeaten home record, stretching back to 2001, was under severe threat.
Now I'm not so sure.
Jonathan Agnew was speaking to BBC Sport's chief cricket writer Stephan Shemilt in Karachi