Novak Djokovic fears Nick Kyrgios's "unreadable" serve and was left seeking a solution to it when the Australian beat him twice in two weeks, Craig O'Shannessy, a former member of the Serbian's team, said ahead of their Wimbledon final.
Kyrgios served up 25 aces to beat Djokovic in their first career meeting in Acapulco in 2017, days before firing down 14 aces to secure his second victory over the 20-times Grand Slam winner at Indian Wells.
The two have not faced each other since, meaning Kyrgios leads 2-0 in their head-to-head.
Tennis strategy analyst O'Shannessy, who was a part of Djokovic's team for both of those matches, said the world number three had asked him to analyse the Australian's serve and identify any clues that could help him to read it better.
"Whether it's his feet, the ball toss -- anything different or any tell with where he's serving," Australia's Sydney Morning Herald quoted O'Shannessy as saying. "I ran overlay of Nick serving out wide and down the middle, and there's no difference.
"Novak was adamant there has to be something that you can read from Nick's serve, but we found literally nothing. The wide serve and the T serve happen off the exact same toss. And because Nick's motion is so quick, it's unreadable.
"And Novak fears that service game. He absolutely does and that's self-evident with Novak nominating Nick as the best serve he's played against."
O'Shannessy added that Kyrgios's ability to vary the speed of his second serves could also prove to be a challenge for Djokovic when they meet in the final of the grasscourt Grand Slam on Sunday.
"That second serve is arguably a bigger weapon because Nick's confidence and willingness to switch things up, no-one else does that when really they should be trying it," O'Shannessy said.
"He's got the game to really worry Djokovic and really go all the way."
