The 57-year-old tennis legend - who was freed from jail and deported back to Germany from Britain in December 2022 under an early release scheme after serving only eight months of his two-and-a-half year sentence for breaching bankruptcy rules - had coached the Serbian sportsman to six grand slam victories and followed his progress on TV during the tournament.

And when Novak beat Nick Kyrgios in the final game, Boris was overwhelmed by emotion because of the reaction from his fellow inmates, with the prisoners banging on their cell doors whenever Djokovic won another big point.

He recalled to The Guardian newspaper: “I wasn’t afraid any more. And when Novak won, and raised his arms, I stood up and raised my arms too. As I did so, the noise along the wing broke out again, louder than ever before.

"The banging didn’t stop for 10 minutes. On walls, on doors. With cups, with chairs.

"It had taken me two weeks to educate them that this was my man, and now I realised. They had understood. I stood there and I cried.”

Boris was grateful to his former protegee for arranging for his now-wife Lilian and eldest son Noah to be in his box for every match.

He said: "“I saw them ringside at every game and that’s what I call true friendship, that you’re not forgotten. I always thank Novak for this special memory.”

Boris doesn't believe the 38-year-old player should be considering retirement yet because he is still very important to the game.

He said: “Look, I think he’s important for tennis today. He leads by example and shows the young players the amount of dedication you need to come to the top and then stay on top. He’s still chasing his 25th grand slam and reached all four major semi-finals this year and won two tournaments. Who are we to challenge Novak when to stop? I heard the other day that he wants to play at the Olympics in LA 2028. Let him. We need him.”