Coach Simone Vagnozzi is excited about working with Jannik Sinner as he thinks the Italian has a high ceiling and a room for improvement. Vagnozzi is just 20 years old but he is already a top-10 player and a five-time ATP champion. Vagnozzi mentioned that Rafael Nadal, Novak Djokovic and Roger Federer managed to improve their games after hitting 30. That’s why Vagnozzi believes Sinner has a room for improvement and can definitely become a better player. “Jannik doesn’t have to be a bad copy of Nadal, Medvedev, Djokovic or anyone else,” Vagnozzi said on Supertennis. “He has to be the best version of himself. “He can improve the serve, the safety in the descent to the net, the technique in the execution of the volley.He can improve the backhand slice, which can help him even if it will not be a shot that will play a lot. Tactically he can i …