Some of his on-court antics would suggest he’s going to get into a fight sooner or later so it probably shouldn’t come as a huge surprise to see tennis bad boy Nick Kyrgios taking to the the boxing ring.

Kyrgios posted a series of shots on his Facebook page, going toe-to-toe with an unnamed opponent in a sparing session.

“This happened today, was so much fun!!,” he posted.

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Kyrgios shaped up for some friendly fire. Photo: Facebook

The Canberran has spent much of the last few months fighting – largely for his reputation.

After a dream run to the quarter-finals of Wimbledon in 2014 where he defeated Rafael Nadal, before making another last-eight appearance at the Australian Open this year things have gone south.

There were accusations of tanking relating to a lopsided second set against Richard Gasquet in their All England Club round of 16 match this year, which started the slide in earnest.

That incident was followed by a poor performance at the Davis Cup where he was substituted for his second singles and then the most recent ignominy – getting caught on camera telling fellow player Stan Wawrinka that Thanasi Kokkinakis had slept with the Swiss’s girlfriend.

The 20-year-old didn’t spell out where he was completing his boxing training but with the hashtags of #Bahamas and #Rusty he may well be in the Caribbean with new mentor and former Australian No.1 Lleyton Hewitt, who calls the archipelago his home.

Kyrgios is scheduled for a week off before taking part in the final grand slam of the year, the US Open, starting September 1 (AEST).

Here are some shots of Kyrgios boxing (black trunks):

*** boxing photos via Kyrgios’ Facebook page

-AAP