SHANGHAI (Reuters) - Nick Kyrgios has been fined US$16,500 (S$22,876) by the Association of Tennis Professionals for breaching the ATP's code of conduct during his defeat at the Shanghai Masters on Wednesday.

The Australian was beaten 6-3, 6-1 by Mischa Zverev in a second-round match in which he put in a series of half-hearted serves and appeared to be walking off court before the unseeded German had returned the ball to him.

Kyrgios also clashed with a spectator before being booed off the court after his defeat.

"Kyrgios received the onsite maximum fine of $10,000 for lack of best efforts, as well as $5,000 for verbal abuse of a spectator and $1500 for unsportsmanlike conduct," an ATP spokesman said.

Kyrgios has made as many headlines for his off-court antics as for his exciting tennis during his brief, but turbulent, career.

The 21-year-old pulled out of the 2016 Rio Olympics after a public spat with the Australian chef de mission Kitty Chiller, who said some of Kyrgios's social media posts suggested "he doesn't really understand what it means to be an Australian Olympian".

At Wimbledon this year, Kyrgios was involved in a heated row in his post-match news conference after being challenged about his behaviour and language, which earned him yet another code violation during his second-round victory over Dustin Brown.

His attitude was also questioned after he capitulated in his subsequent match against Andy Murray, rushing between serves and appearing at times to throw in the towel.