French Open '19: 3 possible heirs to Rafael Nadal's throne

#2 Alexander Zverev

Alexander Zverev won the ATP Finals 2018

The 6 feet 6-inch German professional tennis player, at the tender age of 21, is the world number three on the ATP men's singles chart.

Alexander Zverev has won 10 ATP singles titles and two doubles titles. He has also won the ATP finals last year defeating Roger Federer and Novak Djokovic on the path to glory.

His career has had a lot of ups and downs such that many believed that he is not consistent enough to become a top player but the big three-Federer, Nadal and Djokovic has praised Zverev and reckoned him as one of the best in the future.

In 2017, Nadal told reporters after the five-set victory over Zverev in Australian Open.

, "He is the future of our sport and the present too."

Federer praised Zverev after defeating him in the group round tie in 2017 ATP finals,

"What I like about Zverev is he's got the full package, He's already third in the world. I think he's going to leave the World Tour Finals, regardless if he qualifies for the semis or not, with a lot of information. I think the last six months of the season gave him everything he needs to work forward to. Then, of course, he's only going to get stronger from here. That should be very encouraging for him and his team."

Djokovic applauded Alexanders's 2018 ATP finals title victory,

" There's a lot of similarities in terms of the trajectory of professional tennis, in our careers. Hopefully, he can surpass me. I sincerely wish him that. He seems like someone that is very dedicated. Without a doubt, he's a really nice person, someone that gets along very well with everyone. He deserves everything he gets so far. There's a lot of time ahead of him. I wish him to stay healthy and obviously win a lot of titles. Of course, he won a huge tournament, but he always had the quality to win a Slam. There's no doubt he will be one of the favorites at every Slam."

Apart from winning in London in 2018, he doesn't have a lot of achievements to showcase his can upstage the big three off their perch but he is still very young and an upset at Roland Garros could be on the cards.