John Isner believes Novak Djokovic is "serving better now than he ever has", feels Ivanisevic has played a big role in improving Serb's serve 

John Isner recently analyzed the serves of several top players, including Novak Djokovic and Daniil Medvedev. Isner believes Djokovic is serving better than "he ever has" before, and credited Goran Ivanisevic's input for the Serb's improvement.

Isner is widely regarded as one of the greatest servers in the history of men's tennis. The American has served the second most aces in the history of the sport, behind only Ivo Karlovic.

Novak Djokovic's serve, on the other hand, was one of the weakest on tour when he started out. However, the Serb has worked extensively on that shot in recent years with coach Goran Ivanisevic, and now boasts amongst the finest serves on the circuit.

Djokovic has won 76% of his first-serve points in 2021 so far and has successfully closed out a mammoth 86.6% of his service games.

Speaking to the ATP ahead of the season-ending championships, Isner pointed out that Djokovic hired Goran Ivanisevic - one of the greatest servers in tennis - to help improve his delivery. The American feels Ivanisevic's addition has paid dividends as Djokovic has drastically improved his serve in recent years.

“He's (Novak Djokovic) actually someone who's definitely improved his serve as his career has gone on,” said Isner. "He's also someone who got to World No. 1 and is always trying to get better. In the case of the past few years, he's tried to improve his serve. Hiring Goran Ivanisevic is a big part of that. He has improved his serve. We saw at the Australian Open him holding serve with relative ease right throughout that tournament."

Isner feels the improvements Djokovic has made have given him the confidence to go for bigger second serves in crucial moments.

John Isner at the 2021 Laver Cup

The American highlighted that Djokovic does not need to rely on his serve as much as other players, considering how strong other elements of his game are. However, Isner added that winning a few cheap points always helps since Djokovic expends a lot of energy in rallies.

“Of course, when you hold serve like that and everything else in your game is the best in the world, you're going to win a lot of matches," Isner added. "His serve has certainly improved. He's probably serving better now than he ever has. He has a lot more confidence to go for big second serves and he's winning a lot more free points on his serve."

"Not that he really needs to," the American continued. "But he does play a lot of gruelling rallies, so occasionally gets a free point here or there. It definitely helps him out a little bit.”

People like to focus a lot on Novak Djokovic and Daniil Medvedev's speed and backhands: John Isner

Daniil Medvedev prepares to serve at the 2021 US Open

John Isner believes the serves of several top-ranked players often fly under the radar as other facets of their game are almost perfect. According to the American, people place a lot more emphasis on players' other strengths like their speed and backhands.

"The thing that gets lost with a lot of these guys that are No. 1, 2, 3, 4, 5 in the world is their serves aren't really looked at as their weapons because everything else in their game is so solid," Isner said.

"It's kind of like these guys have no weaknesses so people like to focus a lot on Djokovic's speed and Medvedev's speed and their backhands," Isner added. "Rightfully so, but at the same time they serve exceptionally well and the stats back that up also."