Karol Kucera of Slovakia accused line judges of helping 15th seed Lleyton Hewitt during their second round centre court match on Thursday, which former world number one Hewit won 1-6, 6-1, 6-4, 6-1.
And Frenchman Fabrice Santoro also risks a fine after venting his disgust at what he regarded as a suspect decision by spitting in the direction of a line judge during his loss to big-serving Australian Mark Philippoussis.
Philippoussis won an entertaining match 4-6, 6-3, 6-4, 6-2 over the inventive Frenchman to reach the third round.
Kucera, who has been on the men's tour since 1990, claimed there had been six doubtful calls during his match and later said he had questioned chair umpire Norm Chryst after three of them.
"Even the linespeople helped him," Kucera told reporters after his loss to Hewitt.
"I think it was a little bit on purpose," he said.
Kucera also claimed that players in the locker-room had told him television replays confirmed the calls were wrong.
However
SPEAK OPENLY
An ATP Tour spokesman said Kucera could face a fine if his comments were found to be detrimental to the game.
"We encourage players to speak openly in their press conference, but with that freedom comes responsibility," ATP Tour spokesman Paul Macpherson was quoted as saying by The Age newspaper on Friday.
Frustration at Philippoussis's power game also got the better of Santoro, a 16-year Tour veteran, on centre court on Thursday.
He was clearly seen spitting towards a line judge after a foot-fault was called in the fourth set, a gesture which is almost certain to be penalised with a fine.
Australia's Davis Cup captain John Fitzgerald however defended Santoro, describing him as one of the most polite players on the men's tour.
"He obviously made a bit of a mistake, it was an on-the-spot wrong decision that he made," Fitzgerald told Sydney radio 2UE on Friday.
"But he's got one of the nicest characters you could ever meet on the tennis circuit...He just made one mistake," he said.