25. John Isner
The 35-year-old American has been around for a long time, and while he has had amazing wins, he also is slowing down. He has got a few more years, when he can still hit his famous ace with his first serve and his plastering forehand. But, beyond that, even though he added some shots, he hasn’t won a Slam and probably won’t. Years ago I thought he had a chance, but he couldn’t pull it off. He would go deep in the huge tournaments, on the hardcourts and on grass. Still, his backhand is still so-so and at 6-foot-10, he isn’t very fast. He has moments, when he won the 2018 ATP Masters 1000 Miami. That was the best moment of his life. In 2020, he always wanted to play, so if he commits even more, he could reach the top-10 for the last time. It is his decision.
24. Borna Coric
He can be odd, at times. At the US Open, he grinded it over Stefanos Tsitsipas in the third round. So steady. He reached in the quarters, and he thought he could go further. But against Alexandra Zverev, he didn’t return, and was too patient. He lost 6-3 in the fourth. He plays well and then plays mediocre. He went to St. Petersburg, and reached in the final upseting the former Slam finalist Milos Raonic. On Sunday, he was confident, but he couldn’t outhit Andrey Rublev, who was on fire, losing a tough two sets. Over the past two years Coric looked pretty good, but can he finally break into the top 10? Possibly, but he has to take on the role of warrior.
23. Alex de Minaur
In the last three years, the Australian won a good amount of matches, 82-53. He really likes to play and he is working on his attacking game. At the US Open, he took down Karen Khachanov in five exciting sets. Right after that, he lost to Dominic Thiem, who won the championship. Interesting, he likes grass, as well on the hardcourts. He reminds me of former No. 1 Lleyton Hewitt, who would be intense and play for hours. If de Minaur wants to go further, he has to improve his forehand and return, too. He will continue his path into the top 15 if he starts to impose himself.
22. Cristian Garin
He likes the clay and won all of his four titles on the surface. The Chilean won Rio do Janeiro and Cordoba last February. In April 2019 he won Houston, a small event but that was important. He won Munich, taking down Matteo Berrittini. His improvement has been gradual and, at the age of 24 years, he is very good and deadly, but he has to push himself more.
21. Felix Auger-Aliassime
The 20-year-old is ranked somewhat high, but he didn’t win a lot of important matches this year. He can hit it hard but erratically, which is why he didn’t take down any top players, except when he upset No. 13 Roberto Bautista Agut and defeated Grigor Dimitrov this year. That was it. He did not win from the top-10ers in 2020. The rest was a bunch of so-so players. Beyond that, in 2019, he was much better. Clearly, he must have been exhausted, as he was very flat the past three months. Next year, in 2021, the Canadian has to practice a lot, but his coaches might ask him to slow down for a while. He is a fun player to watche, and he loves to play. In January, he will retool and make a major move in 2021.