Nick Kyrgios was defiant in face of criticism after the Australian argued with a spectator during a limp Shanghai Masters loss to Mischa Zverev.
The Australian appeared to give up late on in Wednesday's 6-3 6-1 loss to the German qualifier, at one stage serving tamely before walking off court to give Zverev the point.
His actions drew jeers from the crowd and Kyrgios became embroiled in a row with one onlooker, who demanded the world number 12 "respect the game" and "respect the people".
Kyrgios, who won the Japan Open last week, explained that he was "physically [and] mentally tired".
Not good enough today on many levels, I'm better than that. I can go on about excuses but there are none. Sorry #StillAWorkInProgress-- Nicholas Kyrgios (@NickKyrgios) October 12, 2016
However, when asked if he understood the anger of the crowd, he said: "Not at all. I feel like if they knew what they were talking about they'd be on the tennis court and being successful as well.
"I can't really understand it at all. They don't know what I'm going through, so no, I don't understand it.
"I don't owe them anything. It's my choice. If you don't like it, I didn't ask you to come watch. Just leave.
"If you're so good at giving advice and so good at tennis, why aren't you as good as me? Why aren't you on the tour?'
"You want to buy a ticket? Come watch me. You know I'm unpredictable. It's your choice. I don't owe you anything. Doesn't affect how I sleep at night."
The second-round loss hampered his chances of qualifying for the World Tour Finals, but when questioned if that bothered him, the 21-year-old added: "I couldn't care less, to be completely honest with you."
His mildly bemused opponent, who will now face Marcel Granollers, said: "It was definitely a match that I did not expect was going to go that way. It happened to be a little easier than I expected."
At last year's Wimbledon, Kyrgios courted controversy when he put in minimal effort in one game during the second set of a fourth-round loss to Richard Gasquet.