Roger Federer and Rafael Nadal issued Novak Djokovic warning by Martin Cilic

Croatian tennis player Marin Cilic has issued a warning to Roger Federer and Rafael Nadal that Novak Djokovic's confidence is only going to increase after enjoying good success since 2018.

Novak Djokovic has won the 2018 Wimbledon and the 2018 US Open and started 2019 by winning the Australian Open. The Serbian tennis star won the latest Grand Slam after defeating Rafael Nadal in the final that took place in Melbourne in the month of January.

Marin Cilic says Novak Djokovic has good momentum to overtake Rafael Nadal's tally of 17 Grand Slam titles and Roger Federer's 20 Grand Slam titles. So far, Novak Djokovic has won 15titles.

"Djokovic is going through a great momentum, he came back as the no. 1 and until Wimbledon, he barely defends points, and his confidence will just increase," Cilic said. "I have no idea. All of them are tennis legends. We do not know what will happen tomorrow. Now Djokovic seems in a good position to overtake Nadal and Federer."

Cilic is 30 years old and he discussed his future plans.

"I may help them in the strategy of the game, tactics, technique, training method. I feel I could help more on this aspect, but if it could help the national team, why not?" he said.

On the future of tennis and younger players, he said: "In tennis, everything has gone forward. We are in an era where three players won more titles than anybody has ever done before, and when Pete Sampras got to 14 everyone thought that no one would have managed to get closer to him."

"That's why you should not underestimate younger players who had the 'fault' of happening in the same eras as the best players of all time. Who knows, in a couple of years (Alexander) Zverev, Borna (Coric), (Stefanos) Tsitispas, (Karen) Khachanov will be at the top. For now, it's one or two steps left for them."