But Cilic said one thing all three players have in common is their ability to keep turning the screw no matter how long the match goes on.
“When you are playing Grand Slam matches against them, there are four hours, five hours to be able to match them up,” he said.
“So, in my opinion, those are the things that they are doing extremely well and plus on top of that, their abilities.”
Federer has publicly admitted his main goals this year are to challenge at Wimbledon and the Tokyo Olympic Games.
But 11-time Grand Slam winner Bjorn Bjorg reckons winning the US Open will also be a priority – while Nadal will hope to pull away from his rival on the all-time leaderboard by winning his favourite Slam, the French Open.
