Fans booed Nick Kyrgios off court at the Shanghai Masters after going through with a threat to quit his match if he lost the first-set tie-break.
The Australian lost the tie-break 7-5 to Steve Johnson soon after receiving a warning for smashing two balls out of court in frustration at a line call.
He was also given a point penalty for an audible obscenity in the first-round match.
At the same tournament last year he was fined for his behaviour and banned.
The 13th seed was heard to say he would quit against Johnson if he lost the tie-break and, after his opponent served an ace on his first set point, Kyrgios walked over to shake hands.
Umpire Fergus Murphy asked the Australian if he needed medical help before the player walked off court to boos from spectators.
He later posted an apology to fans on social media, saying he had been struggling before the match with stomach bug.
At last year’s Shanghai Masters, Kyrgios argued with the umpire and a spectator during a match with Mischa Zverev. He was fined $16,500 (£13,533) for his behaviour, which included “lack of best efforts”, and served a three-week tournament ban.
Meanwhile, British number three Kyle Edmund was knocked out by Croatian fourth seed Marin Cilic in the second round in Shanghai.
The 22-year-old, who beat Jiri Vesely 6-3 6-2 to set up the tie with the 2014 US Open champion, lost 6-3 7-6 (7-5) in one hour 37 minutes.
British number two Aljaz Bedene progressed to round two after beating Italian world number 39 Paolo Lorenzi in straight sets.
The 28-year-old won 6-1 6-4 in an hour and 13 minutes and will now face German third seed Alexander Zverev, who was given a first-round bye.