The rollercoaster career of Australian tennis player Nick Kyrgios has just taken another turn after the 22-year-old retired following the first set against American Steve Johnson at the Shanghai Masters.

The 13th seed, who lost the first set 7-6 (5), was booed off the court after citing a stomach bug as the reason why he quit.

In somewhat of a bizarre coincidence, Kyrgios had a unhappy experience at the same tournament 12 months ago.

The extremely talented but temperamental youngster was issued a eight week ban and fined $32,900 for his lack of effort against German Mischa Zverev in the second round.

On that occasion his antics included walking to his chair before his opponent had served, and engaging in arguments with fans and telling them to "leave if they did not like what they were seeing."

However the proposed ban was reduced by more than half to just three weeks after agreeing to undergo a 'care plan' with a sports psychologist.

The jury is certainly out whether his on-court behaviour has improved in 2017.

Just a few days ago in the China Open final against world number one Rafael Nadal, after a absorbing first 30 minutes, Kyrgios completely unraveled - picking up a penalty point along the way before losing to the Spaniard 6-2 6-1.

With the threat of another ban looming large, Kyrgios has got onto the front foot to explain his latest retirement - citing a stomach bug - in a statement posted on Twitter.

"Guys, I want to apologise to the fans in Shanghai and those that watched around the world on TV today.

"I've been battling a stomach bug for the past 24 hours and I tried to be ready but I was really struggling on the court today which I think was pretty evident from the first point.

"My shoulder started to hurt in the practice which didn't help either and once I lost the first set I was just not strong enough to continue because I've not eaten much in the past 24 hours.

"I'm hoping to be okay for the doubles and will make a decision tomorrow morning, hopefully off of a good night's sleep which I didn't get last night!"

"I'm gutted to be honest to be honest as I was keen to keep the good momentum that I built in Beijing going and finish the year strong. I'll do what I can to make sure I do."

It is entirely reasonable for a player to retire when they are not feeling 100% on the day but looking at Kyrgios's prior history and his lacklustre general  demeanour, eyebrows will certainly be raised.

The Australian is certainly a tennis enigma. Previously he has stated that he does not love the game and has been heard saying he is bored on court in the middle of a match.

However, place him in the Davis Cup or more recently, the Laver Cup, and he is a man transformed, fully embracing the team aspect (much to do with his love of Basketball), so much so that he has even openly shed tears on court - the deciding tie against Roger Federer in the Laver Cup being the prime example.

Kyrgios is a player that the tennis world and Australian fans are ready to wrap their arms around and embrace, however it has to be asked -

Does Nick Kyrgios really want the admiration that comes along with being a top line tennis player, or he is more than happy to march to his own beat?

The talent is there but only Kyrgios himself can set it free it for everyone to enjoy.