The level in question is Chelsea. The player is Christopher Nkunku, who will join the Blues from Bundesliga side RB Leipzig on 1 July. Yet the 25-year-old’s journey began on the outskirts of Paris, arguably the most fertile breeding ground of talent in the European game.

‘Think of the players,’ says Cattenoy, who coached Nkunku in the youth set-up at Paris Saint-Germain. ‘Paul Pogba, N’Golo Kante, Blaise Matuidi, Kingsley Coman, Kylian Mbappe, Christopher, and many more. The player pool in Paris is the best in the world and the competition for players is big.’

Nkunku’s first club was the unassuming AS Marolles. And to understand how he was different from his other young teammates, all you had to do was count the cars.

The previous season they were scarce and travelling to and from matches proved a logistical challenge for several young players. Yet after Nkunku joined, things were very different. ‘We had more cars than players – everyone wanted to see him play,’ Lionel Aubert, Nkunku’s first coach, told La Republique de Seine-et-Marne last year.

Our new signing would spend six years with AS Marolles – and another with Fontainebleau. Then came Paris Saint-Germain and Clairefontaine, France’s national academy.

It was at the under-15 age group that Cattenoy would work with Nkunku. He was left hugely impressed.

‘It was fantastic to coach him,’ Cattenoy, who is now a scout for MLS side Chicago Fire, tells us exclusively. ‘He was a very nice kid, always very motivated, always very passionate about football, always very respectful. He had good support from his family, which is always important for a young player.

‘At that age, he was quiet but quickly found his place in the group. All the players at Paris Saint-Germain liked him; he had a good personality as well as being a good player. And it’s easy to be part of the group when you are a player like Christopher.

‘It was easy to see his talent. He developed physically later than many of his teammates, but he could compensate for that with his technique and vision for the game. His other physical attributes were very strong; he was quick and had very good endurance. He had all the skills and a strong mentality, a strong character, that would help reach a very high level.

‘I remember we played the Paris Cup final at Clairefontaine against Brittany, a good amateur club with very strong players. It rained all day and the pitch, even though the pitches at Clairefontaine are excellent, was flooded. It was really tough to play, but Christopher was still able to show his qualities.

‘The game ended 1-1 but we won on penalties. I believe that was Christopher’s first trophy with Paris Saint-Germain and you could see the happiness in his eyes. I think it was an important experience, a first big success for him.’

There was the opportunity for another in 2016 when Nkunku and Chelsea crossed paths in the UEFA Youth League. Nkunku started the final in Nyon in midfield and won a first-half penalty for Paris Saint-Germain. Yet it was the Blues – for whom Trevoh Chalobah and Mason Mount were on the bench – who came away 2-1 winners.

Nkunku had already made his senior debut for Paris Saint-Germain at that stage and became a regular in the first-team squad in the three seasons that followed. Titles were won, trophies were lifted.

However, in the summer of 2019, Nkunku departed for RB Leipzig, who had finished third in the Bundesliga the previous campaign.

‘As a coach, when a player from the academy plays in the first team, wow, you are very proud,’ reflects Cattenoy. ‘But after that, to see a player go abroad, have success and then to play with the national team, it’s amazing.’

Throughout his first campaign at Leipzig, Nkunku was utilised as a creator. He ended 2019/20 with 13 assists, four of which came in one match against Schalke. The Frenchman became only the second player in recent Bundesliga history to achieve that feat.

Leipzig finished runners-up the following season. Significant change then followed. Coach Julian Nagelsmann departed and influential figures Dayot Upamecano, Ibrahima Konate and Marcel Sabitzer moved on.

Nkunku’s importance grew – and even more so after new head coach Jesse Marsch deployed the France international in a more central role. 

‘With that change of position and change of style, he became the key player and started scoring from the first moment,’ explains Christopher Vivell, who spent two years at Leipzig before joining Chelsea as technical director in December.  

‘He was ready for that responsibility and took this next step in a top way. The team believed in him, and he led through his quality. In training you would see it every day. The special thing is that his performances did the talking.’

The 2021/22 campaign proved the most productive of Nkunku’s career. He was named Bundesliga Player of the Season after scoring 20 goals and registering 13 assists. He also claimed the German PFA Player of the Season after helping Leipzig win the DFB Pokal.

Nkunku ended that season with 51 goal involvements and had established himself as a regular in the France squad. A strong start to the 2022/23 campaign ensured he was selected for the World Cup, but a cruelly-timed injury sustained in training with his international teammates ruled him out of the tournament in Qatar.

He bounced back to help RB Leipzig finish third in the Bundesliga – and two goals on the final day against Schalke ensured Nkunku ended the season as joint-leading scorer in the German top flight.

Nkunku’s final outing for Leipzig came in the DFB Pokal final against Eintracht Frankfurt. Fittingly, he signed off with the vital opening goal and another trophy win. Next comes Chelsea.

‘It is amazing how he developed in his four years in Leipzig, but he needed that time,’ adds Vivell. ‘I describe it like a battery: he was loading, loading, loading and now the battery is full. He’s at the top level.’