Stefanos Tsitsipas and his team were outfoxed by officials at the Australian Open during his dramatic semi-final defeat to Daniil Medvedev.
The Greek player was handed a coaching violation in the fourth set, after match organisers seemingly sent someone undercover to sit below the box where his coaches and family were situated.
The drama over him receiving guidance between points and games had already erupted earlier on when Medvedev, who had taken the first set 7-6, ranted furiously when 4-5 down in the second.
Believing his opponent was receiving tips from his father Apostolos, Medvedev, Medvedev demanded umpire Jaume Campistol issue a violation, yelling “His father can talk every point! Bro, are you stupid? His father can talk every point! His father can talk every point! Can you answer my questions please? Can his father talk every point?”
His request didn't appear to make any difference, with Tsitsipas closing out the set at 6-4 before the Russian responded by taking the third via the same scoreline.
But early in the fourth set, the violation did come, after a tournament referee was sent with Eva Asderaki-Moore - who is Greek - to investigate if any potential coaching was going on.
Indeed, Azderaki-Moore was spotted ordering umpire Campistol to action the disciplinary measure, which drew a wry smile from Tsitsipas.
He wasn't jovial after Medevedev romped home 6-1 in the fourth though - with relations clearly icy between the pair when they shook hands afterwards.
In his post-match press conference, Tsitsipas, 23, denied he had been receiving coaching and suggested Medvedev's rant was a "tactic."
ABC reporter Tyson Whelan posted a clip of what transpired on Twitter, along with the wording "A successful sting operation," and the video prompted a mixed response from tennis fans.
"Loved the way she sits down once the camera got her and the umpire called a coaching code violation. Brilliant work," said @bilal_khattak87, while @30_carolyn posted "Maybe dad should stay home."
@Walksy1 argued the occurrence was nothing new, saying "Ignorant father, he’s done this consistently over many matches."
This isn't the first time the world no 4 has courted controversy at a Grand Slam, infuriating Andy Murray at the US Open with his frequent toilet breaks.
Medvedev meanwhile, will face Rafael Nadal in Sunday's final - after the Spaniard overcame Italian Matteo Berrettini in four sets.
