2. Stefanos Tsitsipas
Greece's Stefanos Tsitsipas caused the biggest shock of the opening week of the 2019 Australian Open when he defeated Roger Federer in four sets in a fourth-round match. Tsitsipas went all the way to the semi-finals in Melbourne where he suffered a chastening straight-sets loss to Nadal. The 21-year-old confessed that the defeat was a blessing in disguise as he returned to the drawing board and summoned his artistry and will to win.
Tsitsipas reached six finals in 2019 following that trouncing at the hands of the Spaniard, winning titles in Marseille and Estoril before his breathtaking run to the title at the Nitto ATP Finals in London. In the midst of that success, he did get his revenge over Nadal in Madrid.
Can Tsitsipas go one better and win his first Grand Slam in 2020? Possibly. The young Greek has notched up a handful of victories over the Big Three in 2019. He beat Federer in the aforementioned Australian Open fourth round and the semi-finals of the ATP Finals. He also has multiple wins over Djokovic
Probable first Grand Slam title: Australian Open/US Open
Did you know: At 21 years of age, Tsitsipas became the youngest winner of the ATP Finals in 2019 since a 20-year-old Lleyton Hewitt won it in 2001. He is also the highest-ranked Greek tennis player ever (currently at World No.6).