As we said earlier, Alexander Zverev is going through a very negative period, both on the court and off the courts. This period lasts at least from the German's victory at the ATP Finals 2018. This season he has had many problems, especially in the Grand Slam tournaments.
Also, there is a head-to-head statistic that should not be underestimated and which, in the coming months, could be a source of concern (and a reason your team will be working on). In fact, in the head-to-head against the Big Three and with three other young players who could be his three main rivals in the future (Nick Kyrgios, Stefanos Tsitsipas and Dominic Thiem), Zverev is not ahead against any of these six players.
Consider the Big Three. With Rafael Nadal, the Spaniard leads 5-0. Zverev has not yet had the chance to beat Nadal, although in 2018 he put in troubles Rafa in Rome. Against Novak Djokovic, the Serb leads 3-2. The last match in the quarter-finals of the French Open 2019, won by Nole.
It's going better against Roger Federer; the two are on the score of 3-3. Considering the other players, Zverev leads against Kei Nishikori (2-1), Marin Cilic (6-1), Kevin Anderson (5-0) and Stan Wawrinka (2-0). The German has a negative balance against Andy Murray (0-1), Milos Raonic (1-2) and Jo-Wilfried Tsonga (1-2).
Let's see what happens against younger players. Against Dominic Thiem, Zverev is on the score of 2-5. It must be said that Zverev won the only ATP Masters 1000 final played between the two, in Madrid, in 2018. Against Stefanos Tsitsipas, the Greek leads 2-1 and won the last two matches played.
Against Nick Kyrgios, Zverev is on the score of 3-4, with Kyrgios winning the only final played between the two, in Acapulco, this season. Against his three young main rivals, Zverev has a negative head-to-head. Zverev leads the head-to-head against Karen Khachanov (2-1), Daniil Medvedev (4-0), Denis Shapovalov (3-0) and Alex De Minaur (4-0).
In general, it is these statistics on which Zverev and his team will have to work a lot, because, if he is destined to become the future number one of men's tennis (but there are many doubts about it), then these numbers will have to be improved.