Australian tennis bad boy Nick Kyrgios has courted controversy right throughout an incident-filled 2015.

From on-court rants and racquet smashes to alleged tanking and that lewd sledge to Stanislas Wawrinka, Kyrgios has been unable to avoid the headlines this year.

And that continued during his four-set loss to third seed Andy Murray at the US Open on Wednesday (AEST).

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While Kyrgios’ tennis was fairly good, his antics – he was warned for swearing, argued with the umpire, smashed his equipment and mimicked sleeping during breaks – again took centre stage.

The glaring public spotlight is not easy to deal with for the 20-year-old and Warne is someone who has also had to get used to constant attention on his every move.

And the legendary leg-spinner, who took 708 Test wickets, offered his advice to Kyrgios in an open letter on his Facebook page.

Kyrgios, who has beaten Rafael Nadal and Roger Federer during his short but action-packed career, has dropped to 37 in the ATP world rankings this year.