Nick Kyrgios makes major injury revelation ahead of January's Australian Open: 'I don't know what's changed'

From the depths of despair, Nick Kyrgios is feeling buoyant again and eyeing a shock Australian Open comeback.

In his first interview since announcing a Battle of the Sexes showdown with Aryna Sabalenka next month, Kyrgios conceded he was feeling the pressure to beat the women's world No.1.

More tellingly, the mercurial former Wimbledon finalist also revealed he'd made a 'miracle' recovery from a career-threatening knee injury and was hoping to be fit for the Melbourne Park major in January.

'Honestly, this has been the first person I've told, I guess, to the media, but the last month for me has been, I don't know what's changed with my knee,' Kyrgios told AAP.

'Like around that Washington period (in late July), I really didn't have hope to be able to play AO or just ever get back to that point of where I felt comfortable and competing and really letting my body go.

'But something in the last month, I don't know what it is. I was with my masseuse and physio last night and something really has changed with my knee.

'Like it's not swelling. It's not feeling bad after a session.'

Restricted to just six matches in the past three years following four rounds of knee and wrist surgery, Kyrgios is ranked No.652 in the world having spiralled outside the top 1000 at one point.

But the one-time world No.13 will play a series of exhibition matches next month against Ben Shelton in Atlanta, Tommy Paul at Madison Square Garden, the World Team Tennis in India and Sabalenka in Dubai on December 28 to gauge his fitness.

'Then if I get through all of that, I'm ready to go,' the tennis showman told AAP at the announcement of his partnership with the Zeus Street Greek restaurant chain.

'I don't know whether to call it a miracle or anything, but my knee feels like it's gotten younger by a couple of years.'

Kyrgios has no idea why his knee has suddenly come good, but says he is finally free in his movement again.

'I felt like something was almost stuck or something. It was just a bit odd and then now, especially the last week and a half or two weeks, I'm back moving and sliding the way I was moving in 2022,' he said.

'So something in my knee is just, you know, I don't want to jinx it, but something in it has gone, kind of allowed me to put three, four days of training together on court for an hour and a half, two hours and be able to actually recover and then build on that.

'So that's it, it has been really exciting and I haven't really told anyone. I have a new lease on life on court.

'Honestly, I'm in a really good space at the moment and, physically, I've been putting in the work.'

The 30-year-old would likely require a wildcard from Tennis Australia to gain entry to his home grand slam, but that would seem a given.

'Look, it's all very raw at the moment, but I literally told my agents yesterday there's a chance that I would love to play Brisbane again in singles (too),' he said.

If he does return, Kyrgios will do so with modest expectations.

'There's no f***ing like: "Oh, I'm gonna win this tournament". Because after the last couple of months, I lost complete hope,' he said.

'I thought my tennis career was literally coming to doubles, whatever, but I thought that that chapter was closing, where now I'm just optimistic again.'

Also reporting that his serving 'wrist is amazing now' too, Kyrgios said it was too early to say if he would ever go deep at another grand slam.

 'I mean, I'm optimistic with the way the way I'm feeling,' he said.

'I genuinely feel like I could at least give myself the chance to get there because of the training.

'That was the issue. I wasn't even able to train and build and even stack days together.

'It was like knee swelling, ice, rest, let's get back on court, let's do the basics.

'Where now it's like, 'OK, I can work on my forehand, I can work on match play, I can work on my returns'.

'I'm actually working on my game rather than my body. I'm training how I was in 2022.'