#3 Karen Khachanov

Russian Karen Khachanov started off the year matching his best performance at the Australian Open, losing in a tough 4-set contest to Juan Martin Del Potro in the second round. He won his second ATP title at the Marseille Open beating Lucas Pouille in the final.
He again beat Lucas Pouille en route to his 4th round loss to Alexander Zverev at the French Open, This was his best ever performance in a Grand Slam. At the Halle Open, Khachanov pulled off a win over Kei Nishikori in straight sets. He matched his French Open result by making it to the 4th round at Wimbledon where he lost to eventual champion Novak Djokovic.
He was one of two youngsters (the other being Stefanos Tsitsipas) who were creating ripples in the tennis world at the Rogers Cup. He made the semis beating the likes of Pablo Carreno Busta and John Isner. Just like Stefanos, Khachanov's run was stopped by Rafael Nadal. He won his second tournament of the year at the Kremlin Cup.
Khachanov's career-defining moment till date came at the Rolex Paris Masters. Despite beating Top-10 players like John Isner, Aleander Zverev and Dominic Thiem on the way to the final, few would have given him any chance of beating top seed Novak Djokovic who was in marauding form.
But that is exactly what happened as he beat Novak in straight sets to win the biggest tournament and prize cheque of his career. His win at Paris meant that he rose to a career-high ATP ranking of World Number 11.
Khachanov will be looking to be the first Men's Grand Slam winner from Russia since Marat Safin.