Nishikori rates world No 1 Djokovic above 20 times Grand Slam winner Roger Federer and Spaniard Rafael Nadal.
The Japanese star is the top seed at the Dubai Tennis Championships this week and he has beaten Benoit Paire in the second round and is set to face No 2 seed Federer who beat Coric in the final of the Middle Eastern competition.
But the star he fears playing the most is Djokovic, who is currently resting after winning the Australian Open.
“Honestly I sometimes kind of wish Djokovic was gonna retire but I never want him to retire due to injury,” Nishikori joked.“Federer and Nadal are strong too, but Djokovic is the most polished player.”
Nishikori also praised compatriot Naomi Osaka for winning the last two Grand Slam titles on the women’s side of the draw.
“I’m surprised at how well Osaka can keep her calm while hitting aggressively,” he added.“That reminds me of my young days, like when I reached the US Open fourth round at the age of 18.“It’s pleasant to watch her playing decisively, I want to play like that.”
Meanwhile, Boris Becker echoed Nishikori’s comments about Djokovic and backed the Serbian to overtake Federer’s Grand Slam haul of which he is five behind.
“Remarkable a year ago he was just going through a break and elbow surgery and was just trying to find his feet again in tennis,” Becker said.
“For him to catapult himself back like that was not to be expected but he is a champion, he has a champion’s mentality.“He knows what it takes to win and he is fully on it. Well, who says Roger is not going to win more than 20?
“Maybe he will come and win Wimbledon this year. So I would not rule it out. Can he do it? Yeah, but so can Rafa.“Rafa has 17 So I think big question marks, these three champions keep winning and until they still play tennis, nothing is sure.”