Back in 2007, Roger Federer, Rafael Nadal and Novak Djokovic finished in the top-3 for the first time, setting the path for total domination over men's tennis in the next 12 years. Since 2004, three legends have missed closing the season at the top only in 2016 when Andy Murray stole the honor, overcoming all the obstacles to keep their game on a high level at the age of 38, 33 and 32, respectively.
Rafa and Novak claimed all four Major titles in 2019 and, together with Roger, five out of nine Masters 1000 crowns, adding more records to their already impressive tallies and cementing the status of the most magnificent tennis trio in history.
Still, the young generation is closing the gap swiftly, with Dominic Thiem and Daniil Medvedev securing three Masters 1000 trophies and reaching Major finals, both losing to Rafael Nadal at Roland Garros and the US Open.
On top of that, Stefanos Tsitsipas conquered the ATP Finals on debut, becoming the sixth-youngest winner of the elite ATP event and securing his place in the top-6 at the end of the season behind the Russian and the Austrian.
For Nadal, those three players should challenge the 'Big 3' for the leading positions on the ATP list in 2020, also mentioning Denis Shapovalov and Jannik Sinner as the players to keep an eye on in the years to come.
"It is normal that there's noise around the young players and it will only get louder because we are getting older every day while they are getting better every day. They have been improving year after year and I think that they can win the biggest tournaments, just like Daniil Medvedev, Stefanos Tsitsipas and Dominic Thiem did this year.
I think Denis Shapovalov will make a big step up in 2020, together with Jannik Sinner who has also made incredible progress. Those players are here to stay. Federer, Djokovic and I are still around but the cycle of life is brutal and at some point that will have to change, sooner rather than later."