Wellington: On-going fitness issues have forced Juan Martin del Potro out of next month’s Australian Open and his planned warm-up event in New Zealand, organisers of the Auckland Classic announced Saturday.

“Juan Martin del Potro has confirmed he will withdraw from the Australasian swing due to fitness issues,” the Classic organisers said in a statement, referring to the two tournaments in January.

“Del Potro confirmed via his management team overnight that he has not had sufficient recovery time and will be withdrawing from the (Auckland) Classic and the Australian Open.”

The announcement came a month after del Potro staged an incredible comeback to down world number six Marin Cilic of Croatia in an epic five-setter to set Argentina up for their first Davis Cup crown.

Del Potro was the 2016 tennis comeback success story. After missing most of last year because of injury, he began 2016 ranked 1,042th and finished at 38th after a meteoric rise which included wins over Stan Wawrinka, Novak Djokovic, Rafael Nadal and Andy Murray.

The 1.98 metre (6ft 6in) del Potro beat Roger Federer in the final of the 2009 US Open and the following year reached a career high of world No. 4 before he began to be troubled by wrist injuries.

Auckland Classic director Karl Budge said it was disappointing for tennis “that these ongoing issues are keeping him off court”.

World No. 8 Madison Keys will miss year’s first slam after undergoing wrist surgery, the American said. Keys, 21, who made the round of 16 at all four grand slam tournaments last year, had the procedure in early November and would not be ready for the season-opening grand slam that begins at Melbourne Park on January 16.

“Three days after the year-end WTA Championships I had minor arthroscopic surgery on my left wrist,” she said on Twitter.

“The procedure was very short, did not involve any tendon issues and went very well ... I don’t want to rush back and need to take my time to be fully ready to perform my best on the court.” Keys, who plays right-handed, also revealed she was being coached again by former world number one Lindsay Davenport, having worked with Thomas Hogstedt for the last year.

“I am very excited about working with Lindsay again,” Keys added. “She’s helped me reach great results in the past and we make an excellent team!”