World No. 1 Serena Williams has been fined 175,000 dollars and put on probation for two years for her outburst upon the judge at the U.S. Open, the Grand Slam Committee said on Monday.

The committee said a further major offense at a grand slam in the next two years would see her suspended from the U.S. Open in 2010, 2011 or 2012.

The fine will be reduced to 82,500 dollars if she commits no further major offense through 2011.

Williams's outburst was prompted by an incident in her semi-final against eventual champion Kim Clijsters at Flushing Meadow in September.

Trailing 4-6, 5-6 15-30, Williams hit a second serve but the line judge called her for a foot-fault, meaning the American had served a double-fault to go match point down.

Astounded by the verdict, Williams launched into an expletive rant at the official. She waved her racket in the lineswoman's direction and then shook a ball in her clenched fist as she threatened to "shove it down" her throat.

"On 9 November 2009, the Grand Slam Committee administrator determined Serena Williams had committed the grand slam major offense of aggravated behavior for her misconduct at the 2009 U.S. Open," the committee said in a statement.

The committee, who are responsible for organizing the four grand slam events, met on Saturday with ITF president Francesco Ricci Bitti at the World Tour Finals in London to discuss administrator Bill Babcock's recommended punishment.

Having already received a warning earlier in the match for smashing a racket, Williams was handed an automatic point penalty for a second violation which abruptly ended the match, giving Belgian Clijsters a 6-4 7-5 victory.

The 11-times grand slam champion issued a statement on the day of the incident apologizing for her behavior, saying she had "handled the situation poorly" although she declined to apologize directly to the line judge.

Such was the fall-out that an automatic ban, possibly even from January's Australian Open, a grand slam she won this year, had been an option.

The only precedent for a player being banned from a grand slam event was when American Jeff Tarango walked off during a match at Wimbledon in 1995 before launching into a verbal attack when he accused umpire Bruno Rebeuh of being corrupt.

As a result, Tarango was fined a then record 63,000 dollars and banned from the following year's Wimbledon.