Alastair Cook, England's former Test captain, believes Jacob Bethell's temperament can make up for his lack of red-ball experience, after he came through a challenging maiden Test in Christchurch with his reputation enhanced.
Bethell was thrust in at No.3 for the first Test against New Zealand, after a hand injury prevented Jordan Cox from making his own Test debut, with Ollie Pope moving down to No. 6 as a makeshift wicketkeeper.
Bethell responded with scores of 10 and 50 not out in England's eight-wicket win, despite having played just 20 previous first-class matches in his professional career, and never having made a century in any senior format.
Cook, like Bethell, was also 21 when he made a century on Test debut against India in March 2006, and went on to miss just one subsequent match through illness while compiling a then-record tally of 161 appearances.
However, by the time of his call-up, Cook had completed a breakthrough home season in 2005, featuring five County Championship hundreds and a memorable double-century against the touring Australians. And speaking on the eve of the second Test in Wellington, for which he will provide studio analysis for TNT Sports, he warned against expecting too much, too soon from Bethell.
"There's a long way to go, but it's been an encouraging start," Cook said. "He's probably a year or two years behind as a player, in terms of knowing his red-ball game. But all of us who've watched cricket and played cricket, have seen something about him.
"It's hard to always pinpoint what it is about certain players that makes you think they've got a really good chance of making it to the next level. But I saw Jonny Bairstow bat as a youngster for Yorkshire, and I saw Jos Butler bat for Somerset … it's not easy to put into words, because it isn't about words. It's about something you see.
"For some, it's the time they have at the crease, for some it's how cleanly they hit the ball. But Bethell's a seriously talented player, and he's looked at home in international cricket straightaway. He's plays the situation in front of him, and he's not overawed by what is going on."
That was apparent even in the adversity of England's first innings at Christchurch. Bethell arrived in overcast, swinging conditions, after Zak Crawley had been dismissed for a duck, and ground his way to 10 from 34 balls before receiving a brute of a delivery from Nathan Smith, in the final over before the lunch break.
"I was impressed," Cook said. "Particularly the way that he gutsed it out in the first innings. His strike-rate in red-ball cricket is actually under 50, so it's clear he likes to build an innings [even though] his array of shots is why he got picked for the white-ball team. There's a huge amount of growth to be had there, without a doubt, even though he's nowhere near the finished article."
Cook himself had been sceptical about Bethell's selection when addressing his call-up in the build-up to the first Test, but admitted that the manner in which he had handled such doubts was further proof of his potential.
"When he got called up, there was some question why [you'd pick] a guy averaging 25 with no hundreds, and that does bring some pressure onto you as a player. To handle that like he's done, it's as if he's doing all the other stuff first, rather than score the actual volume of runs that might have been required [for selection] in the more traditional way.
"A lot of Test cricket is played in the mind," Cook added. "You do need a decent technique, but the power of the mind can overcome a hell of a lot. I don't want to get carried away, but he's obviously made of the right stuff, and you are trusting the judgment of people in that leadership group who have played Test cricket, and wouldn't have taken this risk without thinking that he could cope."
Bethell's calm arrival now increases the scrutiny on Ollie Pope, especially with Jamie Smith due to reclaim the wicketkeeper's duties when he returns from paternity leave in the new year. But Cook acknowledged that Pope's glovework in the first Test had been faultless, while his calm 77 from No.6 turned out to be a vital contribution to England's eventual victory.
"I was pleasantly surprised at how well he kept in that game," he said. "I don't think you should ever get to a case where you've got a fourth-choice county keeper [doing the job for England], but, actually, maybe I've misjudged that situation. He hasn't really made many mistakes, if any, in his four Test matches as keeper.
"So, does that start to be a a viable option down the line as well? Two weeks ago, the XI that played last week wouldn't have been on anyone's list of teams, but things change very quickly in sport, because it is a results-driven business. Pope just looks more suited batting at five and six, while Bethell, in that first innings, had more chance of getting through that swinging, nipping ball."
Watch every ball of the New Zealand vs England second Test, live on TNT Sports and discovery+ from 9.30pm on Thursday, December 5