Nick Kyrgios has pulled out of Rio 2016, accusing the Australian Olympic Committee (AOC) of "unfair and unjust treatment" and "unwarranted attacks".
Kyrgios, 21, joins compatriot Bernard Tomic in withdrawing from the Games.
AOC chef de mission Kitty Chiller had said the pair were "on watch" because of their behaviour.
The world number 19 said he had pulled out with "a heavy heart" as the "AOC has chosen to publicly and privately disparage me".
In a statement on his official website, he added: "AOC's unfair and unjust treatment of me over the last four weeks, as well as the organisation's crystal clear position on whether they want me to be a part of the Australian Olympic team, has solidified my final decision.