It says a lot that, even given how things have gone in Ben Stokes' first nine games in charge as full-time Test captain, No.10 will carry a unique excitement.

At 2-0 the series is won, though Stokes insists Ahmed would have been in contention for this Karachi Test even if the scoreline was 1-1. The nature of a dry surface with low bounce should suit his sharp, flat leggies. And to judge by the character that Ahmed has shown already in his rapid rise to prominence, the pressure of a decider would have been taken in his stride.

Nevertheless, while 3-0 is on the agenda, Stokes is keen to focus squarely on "the process" set in motion from the start of this tour: of engaging, positive and, by and large, attacking cricket. In Ahmed, he clearly sees the embodiment of that, even this early on in the youngster's career. The chance to give him a first taste of international cricket in a controlled environment, and on a pitch that suits his strengths, is too good to miss.

"I think it's a good opportunity for us to not only look at him, but for him to come in and experience what it's like to play international cricket.

"We obviously brought him into the squad to try and get him amongst us and experience what it's like being in this cricket team and we've been very impressed with what we've seen.

"He's got a lot of skill with both bat and ball, so it's great to be able to bring someone with the talent and the excitement that he has into the squad and see what he's got this week."

Much of the anticipation around Ahmed is rooted in the fact that no-one is entirely sure what kind of cricketer he is, or indeed will become. That is partly down to a small sample size of 29 professional matches, 19 of them in the shortest format.

His progression in white-ball cricket is further along than with the red, perhaps highlighted best by the interest he attracted from franchise competitions back in February after impressing with 12 wickets in the Under-19 World Cup. While those options will remain for a good while, his presence on this tour - coming after he registered his first hundred (122) and five-wicket haul (5 for 114) in his most recent first-class outing - is part of a broader plan from the ECB to manage Ahmed's development and to minimise specialisation too early.

"I think being at such a young age, it's great to see someone who has so much freedom in what they do and the way that he bats," Stokes said. "He likes to get on with it and show what he's about and almost - not show off - but show what he can do.

"He's got a vast array of shots. And obviously a wrist-spinner is great to be able to have in your team, especially in these conditions.

"We've taken a look at the wicket as well which looks very dry, I personally think it might spin a bit more than it did in the last Test match but I'm not great at looking at pitches. It's exciting times for Rehan especially, and he was very excited when we gave him the nod that he was going to play last night."

Perhaps the best example of Ahmed's belief was his absence from training on Friday. He awoke feeling under the weather and it was touch-and-go as to whether he would attend the final practice session. The medical staff were keen to ensure the illness was not passed on, especially given how many of the squad have been poorly since arriving into Pakistan. So they put it to Ahmed to see if he felt he needed to train ahead of the big day.

He was happy to miss it because he felt ready. Even though he is being fast-tracked into international cricket, he is taking it all in his stride.