Tennis’ walking wounded have all committed to making the startline of the Australian Open but serious question marks remain about Novak Djokovic and Stan Wawrinka in particular.

Neither man has played a competitive match since Wimbledon, with Djokovic taking the rest of last season off to rehabilitate a troublesome elbow problem and Wawrinka undergoing knee surgery.

Djokovic has remodelled his service action under the guidance of coaches Andre Agassi and Radek Stepanek in a bid to ensure the injury does not resurface.

Now ranked 14th, the six-time Australian Open champion admitted he is unsure how his body will hold up to the rigours of best-of-five-set tennis and hinted he might still need to go down the surgical route.

Djokovic said: “It hasn’t been 100 per cent yet healed. But right now it’s at the level where I can compete, and every day it is getting better.

“I’m hoping that it can be 100 per cent at the start of the tournament. Throughout the tournament, I don’t know how it’s going to behave. Even if it’s 100 per cent healed, after six months of no competition, you never know how you’re going to react. There are some other options, long-term options, that I will obviously revisit and address post-tournament.”

Stan Wawrinka is coming back from injury at the Australian Open
Stan Wawrinka is coming back from injury at the Australian Open (Vincent Thian/AP)

While physical doubts remain, Djokovic hopes his enforced hiatus, during which he became a father for the second time, will mean the end to the mental struggles that dogged him during the second half of 2016 and first half of 2017.

“I haven’t been playing on the desired level,” he said. “But I still know what I’m capable of and I believe in my own abilities to win against the best players in the world.”

Wawrinka’s participation came down to the wire, with the 2014 champion only deciding after practice on Saturday that he would commit to playing his first-round match against Ricardas Berankis.

The ninth seed said: “The fact that I’m here and I’m going to play the first one, it’s a big victory. It’s the best that I could have dreamed when I had the surgery.

“The knee is getting way better. I still have a lot of work to do physically and also tennis wise to be at my top level. I need to start somewhere. It’s a good place to start, to get pushed, to see also mentally how I’m going to react.”

World number one Rafael Nadal was the other doubt after finishing 2017 with knee problems and then pulling out of warm-up events in Abu Dhabi and Brisbane. But the Spaniard, beaten by Roger Federer in a classic final 12 months ago, spoke positively about his preparation.

He said: “It’s the first time I am here without playing an official match in my career. It’s a new situation for me. But I feel good. I feel that I had a good week and a half of practices. I really hope to be ready. I feel myself more or less playing well.”