The world number one insisted those issues, which he was reluctant to divulge, are now resolved but admits the wrist injury remains a concern, with the final grand slam of the year less than three days away.

Djokovic arrives in New York unusually out of form, having bowed out in the third round at Wimbledon to Sam Querrey and the first at the Olympics to Juan Martin del Potro.

US Open
Highlights: Rafael Nadal cruises to US Open title
11/09/2017 AT 06:49

Djokovic: I'm 29, I'm at my peak, and I want to keep it that way

Del Potro is finally bouncing back from his own two-year wrist problem and Djokovic even suggested the Argentinean's chronic issue was "more or less the same injury that I'm encountering."

WATCH THE US OPEN LIVE ON EUROSPORT

Djokovic said: "The wrist hasn't been ideal for the last three and a half weeks.

"But I'm doing everything in my power with obviously the medical team to make sure that I'm as close to 100 per cent as possible during the course of this tournament, at least for the beginning of it.

"It happened actually in Rio, just few days before the start of the tournament. I did experience this for the first time in my career.

Novak Djokovic

Image credit: Reuters

"I've never had this particular wrist injury before. I played against Del Potro, who unfortunately was absent from the tour for the wrist injury himself.

"It was interesting for me to experience how it was and how it is for him for so many years struggling with that essential part of your body as a tennis player.

"After undergoing certain treatments I've gotten better. I'm just hoping that Monday when the tournament starts I'll be able to get as close to the maximum of executing my backhand shot as possible."

Djokovic has been undergoing various treatments to get fit for the US Open, where he begins the defence of his title against Poland's Jerzy Janowicz.

US Open: Men's draw details

His wife Jelena posted a picture on social media on Tuesday of the Serb's left wrist strapped in an electrified bandage.

"There are different methods of healing that I'm considering and consulting," Djokovic said.

"One of them is the physical therapy. What you have seen is the electricity treatments, trying to enhance the regeneration process of the wrist. So that's what it was.

"But sometimes the time is what you need as an athlete, and because the US Open is around the corner, I don't have too much time.

"I try to compensate and improvise as much as I can and find the best ways of getting myself properly ready."

Novak Djokovic says his early Wimbledon exit was down to private issues

Image credit: PA Sport

Even if Djokovic manages to fully recover physically, questions remain about his mental state given the 29-year-old's admission that "private issues" lurked in the background of his Wimbledon exit.

"I apologise but it's tough to go back now and talk about that," Djokovic said.

"It was nothing physical. It's not an injury. It was some other things that I was going through privately."

He added: "It is resolved and everything is fine. I am in a position, like everybody else, like all of you, we all have private issues and things that are more challenges than issues, more things that we have to encounter and overcome in order to evolve as a human being.

"That was the period for me. It happened right there. It was resolved and life is going on."

Novak Djokovic (SRB) of Serbia reacts after losing his match against Juan Martin Del Potro (ARG) of Argentina

Image credit: Reuters

US Open
Top 5: Best shots from Nadal v Anderson
11/09/2017 AT 00:07
US Open
The Coach: How Anderson can shock Nadal in the final
10/09/2017 AT 01:20