Mats Wilander predicted that Novak Djokovic could complete a calendar Grand Slam next year, but only if the Serb wins the Australian Open 2016.

“If Djokovic wins the Australian Open, he has a serious chance to achieve the calendar Grand Slam,” Wilander said, reports Tennis World USA. “If he doesn't win it, then you wonder what's going to happen to his motivation.”

Djokovic was arguably playing the best of his tennis career last season. The 10-time Grand Slam winner started the year with a victory at the Australian Open and rolled on from there.

Djokovic won 11 titles this year, including three Grand Slam titles and six ATP 1000 Masters. Ever since his US Open victory over Roger Federer, “Djoker” has been unstoppable, winning the titles of all the tournaments he joined, most recently at the Barclays ATP World Tour Finals in London.

Gerald Marzorati of the New Yorker believes no athlete had the year Djokovic had in 2015, with the Serb comparably having more success than other athletes around the world like Golden State Warriors and Stephen Curry’s championship run earlier this year and UFC’s Ronda Rousey dominating her opponents prior to her lost against Holly Holm.

“No athlete was as consistently superb, January through November,” Marzorati wrote. “No athlete had the historic year Djokovic did: one of the very best in the Open era of men’s tennis—and, when put in context, the best, or so I’d argue.”

Djokovic will open his 2016 ATP World Tour season at the Qatar ExxonMobil Open in Doha, where the world no. 1 suffered his only pre-final loss of the year against Ivo Karlovic.

Djokovic will be joined by world No. 5 Rafael Nadal, defending champ David Ferrer, Tomas Berdych, and Richard Gasquet at the tournament, which kicks off on Jan. 4-10.

Contact the writer at feedback@ibtimes.com.au, or let us know what you think below.

RELATED STORIES