John DayContributor ISeptember 13, 2009

NEW YORK - SEPTEMBER 12:  Serena Williams (L) argues with Brian Early (R) and Donna Kelso (C) after disqualified for a default during the Women's Singles Semifinal match against to Kim Clijsters of Belgium on day thirteen of the 2009 U.S. Open at the USTA Billie Jean King National Tennis Center on September 12, 2009 in the Flushing neighborhood of the Queens borough of New York City.  (Photo by Julian Finney/Getty Images)

Serena Williams's fiercely competitive nature has brought her 11 grand slam titles, and she has not been shy to question the desire of her fellow professionals, but her intensity on the court has cost her the chance of bringing that number to 12 this week.

The reigning US Open champion was two points away from defeat against Kim Clijsters in last night's semi-final when she was called for a foot fault on her second serve. An enraged Williams turned on the line judge and started waving her racket in an extraordinary outburst, reportedly yelling: "I swear to God I'm ... going to take this ... ball and shove it down your ... throat, you hear that? I swear to God."

Williams had earlier been warned for smashing her racket into the ground and then hurling the mangled wreck at the net post, and this latest tantrum earned her a penalty point, giving Clijsters the match and a place in the final.

Afterwards William said plenty of players shouted at line judges and even questioned the umpiring at Flushing Meadows, saying that she had not been called for foot faults all year but had been pulled up several times over the past two weeks.

Williams may not have earned much sympathy from the country club set but others may feel her treatment was harsh, particularly as replays showed the call to have been dubious. What do you think? Was Serena punished where others would have escaped, or did she get her just deserts?

Personally,I think we have seen far worse behavior from Conners and Mcenroe