Nick Kyrgios had a lengthy argument with umpire Damien Dumusois during his first-round defeat to qualifier Bradley Klahn at the Shanghai Masters on Monday.
Ranked 104 in the world, Klahn presented few problems for Kyrgios in the first set and he looked on course to take out the match.
It didn't end there as Kyrgios turned to Dumusois after hitting an ace and sarcastically asked: "Was that borderline poor?".
The Kyrgios fuse was blown when the umpire issued a soft warning early in the second set for his lack of effort.
He later cautioned the umpire for his comments towards him.
While not a clear-as-day accusation of tanking - like some others have freely done in the past - Dumusois' comments clearly didn't go down well with the 23-year-old.
He left the court using his mobile phone.
It's hard to keep count of all the controversies Kyrgios has been involved in on the ATP Tour - this run-in can certainly be added to the list.
As a result, he was given $US10,000 for unsportsmanlike conduct. On that day, he belted two balls out of the stadium, and walked out midway through the match. On that day, he gave minimal effort on serve, and on one occasion, he even began walking back to his chair before a serve from Zverev.
Kyrgios has a chequered history at the Shanghai Masters after quitting mid-match against Steve Johnson in the first round past year and being accused of tanking in a second-round loss to Mischa Zverev in 2016.
Last week, Kyrgios ceded his spot as Australia's highest-ranked male player to Alex de Minaur following a defeat at the Japan Open.
During last month's US Open, an umpire copped a ban after he gave Kyrgios a freaky mid-match pep talk. A press conference for the Argentine on Tuesday was cancelled at the last moment, however, which suggests that he could still be unwell.Top seed and holder Federer starts his campaign on Wednesday against Russia's Daniil Medvedev.
Big-serving American Sam Querrey struck 14 aces on his way to a 6-3, 6-4 win over world number 16 Diego Schwartzman and set up a second round meeting against his compatriot Taylor Fritz, who beat Robin Haase 6-, 3 7-6 (3).