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.
Williams talks to officials after being handed the decisive penalty point
Kim Clijsters reached the US Open final in dramatic circumstances after Serena Williams received a point penalty on match point for abusing an official.
The Belgian was two points from victory when Williams, who had earlier been given a code violation for racquet abuse, was called for a foot-fault.
Williams launched an angry outburst at the official and got the point penalty, meaning Clijsters won 6-4 7-5.
She will face Caroline Wozniacki who beat Belgian Yanina Wickmayer 6-3 6-3.
Asked afterwards exactly what she had said, Williams insisted: "I don't remember any more, it was in the moment - it was a really crucial point. I haven't really thought about it to have any regrets.
Serena explains outburst
"I didn't think I would get a point penalty, I didn't think about it."
Asked whether she thought the official deserved an apology, Williams said: "From me? How many people yell at linespeople? Players, athletes get frustrated. I don't know how many times I've seen that happen.
"I used to have a real temper, and I've got a lot better. I know you don't believe me, but I used to be worse.
"I'll learn that it pays to always play your best and always be your best and always act your best no matter what.
I said something and I guess they gave me a point penalty and unfortunately it was on match point
"I'm young and I feel like in life everyone has to have experience that they take and that they learn from.
"I like to learn from the past, live in the present, and not make the same mistakes in the future."
After a frustrating day of rain at Flushing Meadows, the women's semi-finals - originally scheduled for Friday - did not begin until 9.21pm local time in New York.
The much-anticipated clash between defending champion Williams and 2005 champion Clijsters, playing only her third tournament after a two-year spell in retirement, took place in front of a relatively small crowd on Arthur Ashe Stadium.
It was the Belgian, 26, who edged a terrific contest for the best part of two sets, breaking serve in game 10 to clinch the first set and recovering an early break in the second.
And with Clijsters closing in on a sensational victory, the pressure told on Williams.
She had been given a code violation for smashing her racquet at the end of the first set and, serving to stay in the match at 6-5 down in the second, her anger resurfaced.
At 15-30 and two points from defeat, Williams missed with a first serve and was then called for a foot-fault on the second to make it 15-40 and two match points to Clijsters.
That prompted the American to move towards the line judge, gesturing angrily and verbally abusing her.
The official then went to the umpire to report what had been said, and Williams was heard to respond: "I didn't say I would kill you, are you serious?"
Williams would later say that this part of the exchange had been a misunderstanding, but she had already done enough to receive a point penalty, which is the automatic next step following a code violation.
I saw Serena talking to the linesman, but I was too far way to hear what she was saying
With US Open referee Brian Earley and Grand Slam supervisor Donna Kelso on the court, Williams went around the net to shake hands with Clijsters before waving to the crowd on her way down the tunnel.
"I said something and I guess they gave me a point penalty and unfortunately it was on match point," she said.
"Clearly in all this year I've never, never been foot-faulted and suddenly in this tournament they give me foot faults.
"I'm not saying I don't foot fault, but it was what it was. I've never been in a fight in my whole life so I don't know why she would feel threatened. I'm clearly not happy."
Tournament referee Brian Earley said: "It was not a default, it was a point penalty that happened to be given on match point.
"There was an earlier warning for racquet abuse and she was called for a foot fault and she said something to a line umpire and it was reported to the chair and that resulted in a point penalty.
"It was a code violation for unsportsmanlike conduct."
Clijsters was left looking stunned as she sat on her chair contemplating the bizarre manner of her victory.
"I was trying to stay focused for the match and was facing the other way," she said.
"I saw Serena talking to the linesman, but I was too far way to hear what she was saying so I can't really comment on what was happening out there."
She added: "The timing is unfortunate, to get a point penalty at the time. But there are rules, and it's just unfortunate that it has to happen on a match point."
It took the shine off a tremendous performance from the Belgian that makes her the first woman to reach a Grand Slam final as a wildcard.
Clijsters also defeated Venus Williams on her way to the final of the tournament, which she won on her last visit in 2005.
And she will go into the final as favourite against Denmark's Wozniacki, the ninth seed, who had never been past the fourth round of a Grand Slam before this week.
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