Kei Nishikori has won 12 singles career titles so far, with 2014 marking his most successful season so far.
Aside from winning five singles titles, he has also finished runners-up in nine other finals, the most notable of those being the 2017 ATP World Tour Finals.
With hard court as his favourite and double-handed backhand as a favourite shot, Krajinović is often compared to Andre Agassi
While the Canadian has not won a grand slam so far, he is the first player from the nation to reach the quarter-finals of the US Open.
Overall, he's won a total of 6 titles - four in singles and two in doubles but where he can improve is in his Grand Slam showings.
At 17 years and one month, he is the second-youngest player to win multiple Challenger titles, and also is the youngest player to defend one.
The 23-year-old Norwegian won five ATP titles in 2021 and made it to the semi-finals of a couple as well.
Matteo Berrettini became the first Italian man to reach a grand slam final since Adriano Panatta won the 1976 Roland Garros title.
Rublev has been near the top of the mountain of men's tennis for quite a while now and has played against some of the best.
The 97-year-old Ukrainian, who wishes to live till 100, has also survived the second world war.