With that deadly, determined in-game gaze, the previously affable, almost timid teenager Kai Havertz is immediately transformed.

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As a 17-year-old, the Aachen-born boy became Bayer Leverkusen's youngest top-flight player and goalscorer, appeared in 24 Bundesliga games and made his UEFA Champions League debut for Die Werkself at Wembley.

Pundits and professionals alike see a star in the making, but Havertz is keeping his steely stare on the step-by-step process that is certain to lead to success.

Watch: Kai Havertz has the Bundesliga at his talented feet!

"Quite a lot has happened to me that you start to think and ask yourself, is this really happening?" the recently turned 18-year-old said.

A slew of solid performances in Leverkusen's first team led to an April TagHeuer Bundesliga Rookie of the Month nomination and ended with Havertz signing professional terms at the club he originally joined as an 11-year-old.

A midfielder who operated through the middle, out wide and up front for Leverkusen in 2016/17, Havertz registered four goals in his maiden top-flight season in Germany.

Rapidly developing a reputation for his astonishing technique, superb reading of the game, strength in the air and overall confidence, excitement abounds as to what the coming campaign holds for Leverkusen's wily wunderkind.

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"Kai has exceptional abilities and is already blessed with a footballing maturity that sets him apart from other players of his age," Leverkusen's sporting director Rudi Völler said of the former Germany Under-16 and U-17 star.

"I've never seen such a complete player at the age of 17," club captain Lars Bender added.

A Matchday 34 Goal of the Week winner against Hertha Berlin – part of a Havertz double strike in an emphatic win against the capital side on the last day of the season – followed a crucial goal in the 1-1 draw against Ingolstadt two weeks before.

His volleyed equaliser in the spectacular 3-3 draw against Wolfsburg in April sent the thrilling teen into Leverkusen's record books, replacing Julian Brandt as their youngest ever scorer at 17 years and 126 days.    

Watch: Havertz's final-day brace against Hertha

In possession of the ball on average 66 times, Havertz – whose style is sometimes compared to that of former Schalke and Werder Bremen schemer Mesut Özil – clocked up 1450 Bundesliga minutes and his impressive aerial prowess was highlighted when winning 59 per cent of his aerial duels, in the style of Leverkusen predecessor Michael Ballack.

"He's very intelligent, he reads the game well and plays the right passes," veteran Leverkusen striker Stefan Kießling said. "He's technically gifted, growing physically and improving all the time, despite the added stress of his [school] exams this year," Kießling continued.  

"It's been a fantastic experience," Havertz said of his journey from registering 19 goals in Bayer's youth team to performing in front of packed Bundesliga crowds on a weekly basis. "It's not easy to get everything right, but I've had great support here. During training I see how much potential I still have to realise."

A frightening thought for his opponents, but a boon for Bayer Leverkusen.

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