That's exactly what happened early in the second set, leading to an argument between Williams and the chair umpire, a scene less ugly than - but reminiscent of - the American's tirade two years ago at the same tournament. In the end, Stosur beat Williams 6-2, 6-3 Sunday in a surprisingly lopsided upset for her first Grand Slam title.
Hitting powerful strokes from the baseline, and looking fresher than the far-more-accomplished Williams right from the start, the ninth-seeded Stosur became the first Australian woman to win a major championship since Evonne Goolagong Cawley at Wimbledon in 1980.
Only 2-9 in tournament finals before beating Williams, Stosur made the U.S. Open the third consecutive Grand Slam tournament with a first-time women's major champion, after Li Na at the French Open, and Petra Kvitova at Wimbledon.
"She played really, really well. I mean, I don't think she's ever played that well," Williams said. "Maybe she has; I haven't seen her play that well."
Indeed, the biggest victory of Stosur's career so far likely will be recalled by everyone else for Williams' latest dispute with an official at Flushing Meadows.
Down a set and facing a break point in the first game of the second, the 13-time major champion hit a forehand and shouted, "Come on!" as Stosur reached down for a backhand. Chair umpire Eva Asderaki ruled that Williams hindered Stosur's ability to complete the point and awarded it to Stosur - putting her ahead 1-0 in that set.
Williams went over to talk to Asderaki, saying, "I'm not giving her that game."
Williams also said: "I promise you, that's not cool. That's totally not cool."
Some fans began booing, delaying the start of the next game as both players waited for the commotion to subside.
Tournament director Brian Earley said Asderaki's ruling was proper, according to U.S. Tennis Association spokesman Chris Widmaier.
During the changeover two games later, Williams continued to talk to Asderaki, saying, "You're out of control. ... You're a hater, and you're just unattractive inside."
"If you ever see me walking down the hall, look the other way," it sounds like Williams threatens.
Williams also told the official: "Really, don't even look at me."
Asderaki issued a code violation warning for verbal abuse, and the Widmaier said Earley would speak to the chair umpire and review tape to determine whether Williams would be fined. That decision will be announced Monday.
At her news conference, Williams rolled her eyes while deflecting a question about whether she regretted what she said to Asderaki.
"I don't even remember what I said. It was just so intense out there. ... I guess I'll see it on YouTube," Williams said.
When Stosur wrapped up the match with a forehand winner, Williams refused the customary post-match handshake with the chair umpire.
This sort of thing has happened before at the U.S. Open to Williams, who won the tournament in 1999, 2002 and 2008.
In the 2009 semifinals against Kim Clijsters, Williams was called for a foot-fault that set her off on a profanity-laced outburst at a line judge. Williams lost a point there, and because it came on match point, Clijsters won.
That led to an immediate $10,000 fine from the U.S. Tennis Association and later a record $82,500 fine from Grand Slam committee director Bill Babcock, who also put Williams on a "probationary period" at Grand Slam tournaments in 2010 and 2011, saying that fine could wind up doubled.
A poor call during Williams' 2004 U.S. Open quarterfinal loss to Jennifer Capriati was cited as a main reason for the introduction of replay technology in tennis.
The Associated Press contributed to this article.