Former eight-time ATP champion Todd Martin thinks that Novak Djokovic will become a record Grand Slam champion one day. Roger Federer, 37, holds a record of 20 Grand Slam titles captured, while 32-year-old Rafael Nadal has won 17 Major titles so far in his career.

Djokovic, 31, is tied at the third place with Pete Sampras with 14 Grand Slam titles captured. The Serb ended his two-year Grand Slam title drought this past Wimbledon when he won it all at The All England Club to capture his first Major title since the 2016 French Open.

The former world No. 1then followed his Wimbledon success by winning his first US Open title since 2015. "I think if he stays at that level, he'll get past. In professional athletics, if you're not getting better, you're getting worse," Martin told exclusively to Metro.

"II think if he can maintain – and this is the most amazing thing about Federer and Nadal over the years and the impressive thing Novak displayed in that handful of years that he was pretty dominant – the constant desire and I would almost portray it as a need, an internal and intrinsic need to get better. "I think if Novak can maintain that mentality, records are definitely attainable." Also read: Bernard Tomic: It's amazing to prove so many people wrong