Serena Williams explained her outburst at Greek umpire Eva Asderaki in Sunday's US Open women's final in a Twitter posting on Wednesday, saying she lost control of her emotions.
Australian Samantha Stosur coasted to a 6-2, 6-3 triumph over the American 13-time Grand Slam singles champion, who directed a series of insults at Asderaki in the second set.
"My emotions did get the best of me this past weekend when I disagreed with the umpire," Williams said. "It has been a long road to get back to the US Open this year, and I am thankful to have had such a great two weeks in New York."
Williams, who turns 30 on September 26, was fined $2,000 for a code violation for verbal abuse for her comments.
She was on probation after a 2009 US Open semi-final outburst but was not banned from next year's US Open because the latest tirade was not ruled a "major offense."
The latest controversy stemmed from Williams hitting a forehand winner and screaming "Come on," while Stosur was lunging for the ball to attempt a backhand shot.
Asderaki said Williams' scream was a hindrance to Stosur and penalized her, handing Stosur a service break.
"Aren't you the one who screwed me over last time?" Williams said, referring apparently to a 2009 match in Doha.
Williams received $1.4 million at the US Open, a runner-up prize of $900,000 plus a $500,000 bonus based upon her results in tournaments leading to the US Open.