When Bayer Leverkusen took on Atletico Madrid and Schalke in April last year, they did so without their prodigious talent Kai Havertz. Then 17-years-old, the attacking midfielder was excused from the Champions League and Bundesliga clashes as he was studying for his school exams.
Big tests are no problem for Leverkusen's youngest ever debutant and goalscorer, whose passing ability has seen him become a regular at Leverkusen and earned comparisons to Arsenal and Germany's Mesut Ozil.
Before he was legally an adult, Havertz had broken into the senior squad at Leverkusen, made his European debut in the knockout stages of the Champions League and netted his first goal for the club. He scored four times in his debut season, and has two league goals so far in 2017-18, but is better known for creating chances than finishing them.
Havertz's distribution is far better than players years older than him, already hitting the 800-pass mark for the season, almost double the tally of the average midfielder in Germany's top flight. He averages just under 35 passes a game, finding a team-mate 81 per cent of the time - both higher than the league average.
Leverkusen are challenging for a Champions League spot this season, with Heiko Herrlich's 3-4-3 and 3-5-2 approaches quickly turning defence into attack. They use the pace of players like Leon Bailey and Karim Bellarabi to break quickly out wide, but rely on 18-year-old Havertz to create chances through the middle of the pitch.
It was Havertz who set up Bellarabi for the Bundesliga's 50,000th goal earlier this season, adding his name to the record books once more. Part of his effectiveness is the fact his right foot is almost as good as his stronger left foot. This allows him to pick out players in good positions and spread the ball in attack. His passing accuracy in the opposition half is an impressive 76%, coming in at 5% more than the league average.
He has created 22 goalscoring chances this season for Leverkusen, and continues to go from strength-to-strength. His prodigious talent has seen him attract the attention of some of Europe's biggest teams, with Liverpool linked to him after their scouts went to watch the midfielder in action for Germany's Under-19 side.
At youth level, Havertz has been head and shoulders above his peers. He has netted six goals in five games at U19 level and is expected to progress quickly into the U21 side and then up to senior level for the world champions.
Havertz has already been a revelation at every level and for every time he has played for, so will surely continue that trend wherever he goes, be it Liverpool or Leverkusen.