After last competing 13 long months ago, Kei Nishikori has admitted in a Tokyo sponsor appearance that he is losing faith in his career.

The 32-year-old who finished runner-up at the 2014 US Open said , though that he took encouragement from the longevity of just-retired Uniqlo sponsor stablemate Roger Federer, who wielded his racquet until age 41.

Nishikori has been dealing with injuries for the last few seasons, with his ranking sagging to outside the Top 1000.

But he said that Federer’s example could be one to follow, with his next goal hopefully the Australian Open in January.

“Seeing Roger, I finally came to think that I can continue playing tennis beyond the age of 30. Of course, I have been on the verge of retirement,” the Japanese player said.

“know when I will return to the circuit. My goal would be to be able to play the 2023 Australian Open, but we are very tight.

“I haven’t trained at the highest level for two weeks due to ankle discomfort.

“Right now the chances of playing the first Grand Slam of the season is 50 per cent. “

Nishikori added: “I’d like to play some pre-tournament tournaments, but I don’t know if I’ll make it in time. 

“If I don’t make it, I’ll start playing some Challenger tournaments in January or February.”

The Florida-based Asian ace who touched fourth in the rankings said that months of inactivity have left his mental state fragile.

“I’ve been very depressed in these last months, I even thought about retiring. From July to September I was in rehabilitation at home.

“There are three months in which I cannot play tennis, I cannot even hold a racket. Mentally it is very complicated.”