"What did I say?" Williams said. "You didn't hear? Oh."
US OPEN
Venue: Flushing Meadows, New York Date: 31 August - 14 September
BBC coverage: Live text commentaries on the website from 1600 BST each day, regular updates on 5 live, full commentary on 5 live sports extra in week two, both finals on 5 live. Live on Sky Sports and Eurosport.
Serena Williams has been fined $10,000 (£6,000) by US Open organisers for her tirade towards a line judge during her semi-final defeat by Kim Clijsters.
The American lost her cool after being foot-faulted at the end of the contest.
Officials, who also fined Williams $500 for racquet abuse in the same match, said further penalties could be imposed once an investigation had taken place.
WTA Tour chief Stacey Allaster called the 28-year-old's conduct both "inappropriate and unprofessional".
Allaster's statement continued: "No matter what the circumstances, no player should be allowed to engage in such behaviour without suffering consequences.
 | As a role model, it's important for a leader like Serena to step forward and recognise her behaviour last night was unacceptable WTA Tour chief Stacey Allaster |
"Serena is a great player who has done so much for our sport and I am certain she will continue to be a role model to millions of young women who want to play the game and excel as Serena has done.
"As a role model, it's important for a leader like Serena to step forward and recognise her behaviour last night was unacceptable."
Williams also released a statement, admitting she had let her emotions get the better of her.
"Last night everyone could truly see the passion I have for my job," her statement read.
"Now that I have had time to gain my composure, I can see that, while I don't agree with the unfair line call, in the heat of battle I let my passion and emotion get the better of me and as a result handled the situation poorly.
"I would like to thank my fans and supporters for understanding that I am human and I look forward to continuing the journey, both professionally and personally, with you all as I move forward and grow from this experience."
The foot-fault call had looked a questionable one with the aid of television replays and it handed Clijsters match point.
 Williams remonstrates with the line judge after being foot-faulted |
As the Belgian wild card waited to play the next point, Williams, who had already been handed a code violation for racquet abuse, decided to vent her frustration.
She unleashed a tirade towards the line judge, briefly walked away and then returned for another blast at the line judge.
Chair umpire Louise Engzell then intervened, asking the line judge what had been said, while tournament referee Brian Earley was also summoned.
The officials eventually ordered a point penalty, the next level of punishment after an initial code violation, which gave the match to Clijsters.
The $10,000 fine is the maximum on-site penalty a Grand Slam tennis tournament can issue for unsportsmanlike conduct.
The Grand Slam committee administrator has also opened an investigation to determine whether Williams' behaviour should be considered a "major offence".
Williams had been unrepentant about the incident in her post-match press conference, claiming to not remember what she had said to the line judge and saying her actions were not unprecedented.
She was later seen entering referee Earley's office before leaving the Billie Jean King National Tennis Centre.
According to the Grand Slam Rule Book, unsportsmanlike conduct when referred to the Grand Slam Committee can be treated as "aggravated behaviour", which "is flagrant and particularly injurious to the success of a Grand Slam, or is singularly egregious."
The rule book states that such a violation "shall subject a player to a fine of up to $250,000 or the amount of prize money won at the tournament, whichever is greater".
It also states that a player can be permanently suspended from play in all Grand Slams and/or the Tennis Masters Cup if found guilty.
Williams, who was beaten 6-4 7-5 by Clijsters, earned $350,000 in prize money for reaching the last four.
The 11-times major winner is also scheduled to play in the women's doubles final on Monday with her sister Venus.
