It is less than two years since Jason Roy had the net session which changed his career. England were in Manchester for the start of a one-day series against West Indies and Roy — dropped two months earlier for the semi-final of the Champions Trophy — was in the squad but not the team.
With him was Graham Thorpe, whom he had known since his teenage days in Surrey's second XI. Thorpe got straight to the point.
'It was like Thorpey had told him: 'Stop trying to bat with your ego, bat with your brain',' says Paul Farbrace, then England's assistant coach.
'It was the most clearly thought-through session he'd ever had. That was the turning point. From then on Jason worked out his game and matured.'
Roy's crack at redemption came sooner than expected. Alex Hales was suspended following his Bristol night out with Ben Stokes and Roy embarked on the no-holds-barred opening partnership with Jonny Bairstow that has propelled England to the final.
Against West Indies, he began with 84 in a stand of 126 at The Oval, then made 96 out of 156 at the Ageas Bowl. On Sunday, against New Zealand at Lord's, he and Bairstow will aim for a fifth successive century partnership.
Thorpe, still something of a father figure, remembers the net session.
'Sometimes you want to let him go out and play,' he says. 'Other times it's about staying longer at the crease and how you go about that. I wanted him to kick on. I knew how dangerous he could be and how good he is to watch.
'I've always loved his ability to strike the ball. He'd do the odd reckless thing, but he's got better and better at putting the pressure back on the bowler.
'He's quite belligerent and can be noisy, but he brings a lot of energy to the team. The odd bat might be dumped on the dressing-room floor, but it is because he is so passionate.' Insiders say Roy has matured since marrying Elle Moore in October 2017. A year earlier, as her husband-to-be grew disillusioned with cricket, she told him to 'stop being an idiot'.
The advice worked, and cricket is no longer his be-all-and-end-all: Elle recently gave birth to Everly, their first child, and Roy is a doting father.
Not that the passion can't tip over into petulance. When he was wrongly given out by umpire Kumar Dharmasena, caught behind in Thursday's semi-final at Edgbaston to end a spectacular 65-ball 85 against Australia, he signalled for a review that was no longer available and had to be coaxed from the middle by umpire Marais Erasmus.
The ICC fined him 30 per cent of his match fee and added two demerit points to the one he had collected because of an 'audible obscenity' against Pakistan. Four points equal a suspension. The prospect of Roy missing the final, after 426 World Cup runs at an average of 71 and a strike-rate of 117, did not bear thinking about.
'I actually got it wrong,' he admitted on Saturday. 'I spoke to Kumar and said I thought we had the review. I didn't realise Jonny Bairstow's lbw wasn't umpire's call.
'It was just a game where I got in, it was a semi-final, I'd worked pretty hard to get to where I am, and that happens. To get out like that was slightly disappointing and I probably showed it more than I should have. But it's pro sport, emotions run high.'
Great things have been expected of him since his family emigrated from his hometown of Durban, South Africa to England when he was 10. Playing for Surrey Under-11s he was spotted by Neil Kendrick, the former Surrey and Glamorgan slow left-armer and head of cricket at Whitgift School in Croydon.
Kendrick persuaded Whitgift to offer Roy a sports scholarship and he became close friends with schoolmate Rory Burns, now his captain at Surrey.
Elle introduced Burns to her friend, Victoria, who will marry him in October, giving Roy the chance to return the favour: be best man. Before that, on August 1, the two will probably walk out together to open the batting in the first Ashes Test.
'That would be pretty cool,' says Burns. 'Jason's in the mix now and I hope I am too. He's always had that talent, but now he's harnessed it and curbed his emotions to get the best out of himself.'
Gareth Townsend, Surrey's academy director, agrees.
'His progress has been unbelievable. He stood out early on as an aggressive, flamboyant batsman whose style was exactly the same as it is now. But the biggest learning he has made with England is his ability to bat through the tricky periods.'
Like Kevin Pietersen, another arrival from South Africa with a taste for flair and a strong sense of self, Roy was not easily pigeon-holed, and Townsend took him out of the academy set-up because he was finding it too prescriptive. But there was never any question of Surrey allowing him to drift away.
If Test cricket is the long-term goal, it first needed England's new white-ball set-up to take a chance on him four years ago. He began inauspiciously, carving his first ball against New Zealand at Edgbaston to backward point, and failed to reach 40 in the five-match series.
But Farbrace, interim coach while England waited for Trevor Bayliss, fought to retain him for the series against Australia.
'I argued strongly that he should stay in because he'd played for the team against New Zealand and never for himself. I've always said that while Eoin Morgan is the single biggest factor behind England's success, Jason Roy epitomises their journey.'
Roy made a couple of sixties against Australia and that November a maiden ODI ton against Pakistan in Dubai.
Since his dropping for the Champions Trophy, highlights have included an England-record 180 at the MCG, successive scores of 120, 82 and 101 during the 5-0 whitewash of Australia last summer, and 114 off 89 balls against Pakistan at Trent Bridge in May.
The Pakistan innings was played on a few hours' kip: Roy had spent the night in hospital after Everly fell ill. Happily, she made a quick recovery.
'Two years ago does feel like another world,' said Roy. 'I feel like a completely different person. I got dropped, came back stronger, and now I'm in a World Cup final. I couldn't have asked for any more, to be honest.'