Frenchman Fabrice Santoro was fined $1,500 (800 pounds) after spitting in the direction of a line judge, one of two incidents in which senior players vented their anger over contentious line calls at the Australian Open.
Santoro was fined $1,500 on Friday, a fraction of the maximum available fine of $10,0000, for unsportsmanlike conduct by the International Tennis Federation during his centre court match against big-serving Australian Mark Philippoussis on Thursday.
Frustration at Philippoussis's power game got the better of Santoro, a 16-year Tour veteran, who turned and spat over his shoulder in the direction of a line judge after disputing a call with chair umpire Andreas Egli in the fourth set.
He was clearly seen spitting towards the line judge after a foot-fault was called.
Philippoussis won an entertaining match 4-6, 6-3, 6-4, 6-2 but the inventive Frenchman Santoro earned A$28,000 in prize money for reaching the second round.
Kucera accused line judges of helping 15th seed Lleyton Hewitt during their centre court match, which former world number one Hewit won 1-6, 6-1, 6-4, 6-1.
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, he also said the suspect calls did not affect the outcome of the match.
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.
Australia's Davis Cup captain John Fitzgerald defended Santoro on Friday, 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.
"But he's got one of the nicest characters you could ever meet on the tennis circuit... He just made one mistake," he said.