According to former World No.4 Nicolas Kiefer, Alexander Zverev has the game to defend his ATP Finals title. "Zverev has known what he has to work on and signing that deal with Roger's company has been good for him.
Now he can focus on his tennis and he is still a top eight player remember, so he's part of the ATP Finals in London," Kiefer said. "To finish the year in the top 10 by not playing his best tennis is a great achievement.
I hope he can get it together for 2020 because if I can pick a player that I think that can make it, then it would be Sascha. With the combination with Roger, he can learn a lot”. He further added, "Roger is aware of Sascha's game; he knows what he is doing wrong and knows how he can improve.
Everything Roger does, he does 100 per cent, so I think he's 100 per cent behind Sascha otherwise he wouldn't sign him. Remember that he is still very young." He also spoke about Danill Medvedev, saying, "Medvedev has been on fire, playing high-level tennis to reach final after final," Kiefer said.
"On the court he is tough to play, so it's good to see another new face”. "The problem for these youngsters is having to adapt to best-of-five-set matches. You have to continue to learn from guys like Federer, Novak Djokovic and Rafael Nadal because they know how to handle it”.