No-one has scored more Premier League headers than Dominic Calvert-Lewin since the start of last season, but his leap to prominence is no surprise to the man who signed him for Everton.
Former Toffees defender and now academy director David Unsworth says he is still "amazed" that he managed to buy the forward from Sheffield United for a "cheeky" bid of a reported £1.5m in 2016.
He first spotted Calvert-Lewin as a 15-year-old in the gym when he was head of the Blades' academy, and quickly realised he was "a talent who stuck out".
"What first caught my eye was his gym work," Unsworth tells BBC Sport. "We'd be there in the evenings and his power from a standing jump was the best I've ever seen. He was doing a lot of squats, and jumps at an incredible height onto these wooden boxes.
"He had a few growth issues - his legs were growing at a different rate to his body - but that was the first time I saw him and thought 'wow, there's an incredible athlete there'."
|Fastest Premier League players this season|
|Player||Top speed (km/h)|
|Tariq Lamptey (Brighton)||36.6|
|Kyle Walker (Man City)||36.6|
|Nathan Tella (Southampton)||35.6|
|Oliver Burke (Sheff Utd)||35.2|
|Aboubakar Kamara (Fulham)||35.2|
|Dominic Calvert-Lewin (Everton)||35.1|
|Jack Grealish (Aston Villa)||35.1|
|Jamal Lewis (Newcastle)||35.1|
|Harvey Barnes (Leicester)||35.1|
|Kenny Tete (Fulham)||35.1|
There is far more to Calvert-Lewin than his athleticism, though. He has since developed into "a complete striker", according to Everton manager Carlo Ancelotti, who has also coached Cristiano Ronaldo at Real Madrid and Filippo Inzaghi at AC Milan.
Calvert-Lewin's nine goals in all competitions this season have helped Everton make a perfect start to their campaign and they sit top of the Premier League table.
It earned the Under-20 World Cup winner his first call-up to the senior England squad, with matches against Wales, Belgium and Denmark over the next week offering a chance for him to impress.
"Every hurdle he has encountered, he has jumped over with ease," says Unsworth.
Overcoming adversity at Sheffield United
Sheffield United may rue the fact they let Calvert-Lewin go, especially as they have just paid a club record £23.5m for former Liverpool striker Rhian Brewster, who is only 20 years old.
In 2014 the Blades were stuck in League One and desperate to get out. The club failed to win promotion under managers Nigel Clough and Nigel Adkins before they struck gold with Chris Wilder. Yet all three preferred tried-and-tested players to youngsters.
It was not an environment to experiment with the likes of Calvert-Lewin, according to Sheffield United's former head of academy Nick Cox. A lack of opportunities caused frustration with the teenager, who was keen to establish himself in the first team.
"We got to a point where his expectations of himself were exceeding the opportunities that came his way," says Cox, who now has the same role at Manchester United.
"He found under-16s and under-18s football too easy and, as a local lad, he was desperate to go route one through the system, but we had to find another way."
So over a cup of tea in the gym one Sunday morning, the pair of them got a white board out and navigated a path to first-team football, which included a change in position for the then midfielder and a pivotal loan spell at Stalybridge Celtic.
Seeing double at Stalybridge
Up until that point, Calvert-Lewin was a box-to-box player but, after further talks with his coach Travis Binnion, they decided to test his athleticism and heading ability as a centre-forward.
It was a challenge which came to fruition in a memorable Stalybridge debut against local rivals Hyde United, which left the 17-year-old Calvert-Lewin with a scar that is still visible today.
Cox called it "a huge turning point". He adds: "Travis and I went to watch the game. It was cold, horrible and Dom froze under pressure of senior level football, then just before half-time he got a whack around his head where he was seeing double and had a big bruise around his eye.
"He was OK, but we immediately saw an issue. He was only there for a month, so if he took an opportunity to come off, he wouldn't be playing much after that. So Travis ran around the pitch and told Dom that if you half-think you can stay on, then do. Don't escape a difficult scenario because things aren't going your way.
"Dom stayed on, scored a scrappy goal from a yard out, scored two in the reverse fixture, which they won 7-1, and ended up scoring five in six games to become a bit of a Stalybridge legend."
Calvert-Lewin adds: "I played the rest of the game with basically one eye because the other one closed up, but that experience for me at the time was the most I ever enjoyed my football.
"It just gave me that sense of what it was to play in front of fans, to play proper men's football, and it was definitely a catalyst in propelling me forward."
What Calvert-Lewin did not know was that Unsworth was at one of those games, and was slowly building an impression of a player he knew was "a diamond".
Polishing the diamond at Everton
Despite a further loan spell at Northampton Town under then manager Wilder, and then a return to Bramall Lane where Wilder followed, opportunities failed to materialise.
So Calvert-Lewin cast aside a chance to play for his home club, instead joining a Premier League side, which showed his "dogged determination" to make it, according to Cox.
Everton was a new dawn and, although in his first season he made only 11 appearances under Ronald Koeman, by the following season (2017-18) he was getting regular opportunities.
But under Koeman, and subsequently Sam Allardyce and Marco Silva the following season, he was in and out of the team and was often played out wide. There was also a weight of expectation after Romelu Lukaku departed the club, which Calvert-Lewin found hard to live up to.
Last season, the Toffees still had faith and handed him the number nine shirt. But when assistant manager Duncan Ferguson took over for a three-game period between Silva's sacking and Ancelotti's appointment in December, everything changed.
The Scot backed Calvert-Lewin as his main striker, gave him added support in a 4-4-2 system and since then, only Liverpool's Mohamed Salah has scored more Premier League goals than Calvert-Lewin's 14.
Unsworth says Ferguson's belief in the young striker and Ancelotti's Champions League-winning expertise has made a huge difference. But it has also allowed Calvert-Lewin to show confidence in his own ability, which Unsworth says has been there from a young age.
"I always believed I could get here," Calvert-Lewin said after scoring in the 4-2 win over Brighton on Saturday. "Sometimes it's about age and maturity. I've been patient. Now I'm reaping my rewards."
Despite his remarkable improvement under Ancelotti, the Italian says he has done "nothing special" with Calvert-Lewin. Yet he has asked him to stay more central on the field so he can be closer to the goal and attempt to score with one touch shots, just like Inzaghi, whom Calvert-Lewin has since looked up on YouTube.
Unsworth adds: "There are loads of things that can make him even better and I would expect Dom to hit 20 goals this season and for every season after that.
"He's the perfect number nine and his confidence is soaring.
"It was a very proud moment for everybody at Everton when Dom got his England call-up. It was long overdue, but he has his chance now and I think he'll be in the squad for a very long time."
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