Top 5 tennis players under the age of 20 

2016 US Open - Day 14

#4 Stefanos Tsitsipas

Rakuten Japan Open - Day 1

A former junior no. 1, Stefanos Tsitsipas is also the highest-ranked Greek player in the world. He has been performing exceptionally well of late as he has reached the main draw of many tournaments.

He qualified for the French Open and Wimbledon this year but lost in the first rounds to Ivo Karlovic and Dusan Lajovic respectively.

He has two Challenger titles to his name in 2017 and reached a career-high ranking of 115 just last week.

He is currently ranked 16th in the race to Milan and will find it extremely hard to qualify for the tournament. However, he will aim to finish the year inside the top 100 and directly qualify for the Australian Open.