Samantha Stosur, a 27-year-old Aussie who has been something of an under-achiever on the world tennis circuit, finally made good in the final of the US Open.

She kept her cool to win her first grand slam title, whereas opponent Serena Williams lost hers in another rant against a courtside official.

Stosur, who has been regarded as physically fit but mentally weak, beat the home favourite and three-times champion Williams 6-2 6-3 with a display of power tennis, launching blistering forehand after forehand. Williams began to lose her game, and her composure, taking out her frustrations on the umpire.

It was the second time in three years that Williams's menacing behaviour towards an official at Arthur Ashe stadium overshadowed her opponent's brilliance. In 2009, Williams lashed out at a lineswoman who called her for a foot fault. On that occasion she lost her semifinal to the unseeded Kim Clijsters when she was given a point penalty on match point.

Sunday's incident was sparked by the rarely invoked "hindrance rule". It came in the second set when Williams hit an apparent winner to stave off another break point, shouting "Come on!" as she hit it.

With Stosur getting part of her racket onto the ball, umpire Eva Asderaki brought into play the hindrance rule, awarding the game to Stosur because Williams had verbally hindered her opponent's ability to complete the point.

Williams objected, which drew a code violation from the umpire. During the changeover two games later, Williams continued to berate the umpire: "If you ever see me walking down the hall, look the other way. You're out of control. You're a hater and you're unattractive inside.

"Code violation for this? I expressed who I am. We're in America last time I checked."

The US Tennis Association said it was reviewing the incident.

After the match, Williams said she had just been "in the zone" at the time and did not remember what she had said.

"It was just so intense out there," she said, adding that she misunderstood the hindrance rule: "I thought it was the hat-drop rule, where if you drop a hat you kind of replay the point."

The confusion over the rule whipped the crowd into a frenzy of boos and catcalls.

Williams, a 13-times grand slam singles champion, had won four of her six previous matches against Stosur.

The tension, the crowd and the fuming Williams did not put off the Aussie this time. She was 15-40 down in a critical fourth game of the second set and fought back to deuce with a blistering first serve that was timed at 178km/h and a forehand that Williams could not pick up. She won the game to take control of the match again.

Stosur is the first Australian woman to win the US title since Margaret Court in 1973 and the first to win a grand slam since Evonne Goolagong in 1980.

• Lisa Raymond, 38, surpassed Billie Jean King as the oldest grand slam women's doubles champion on Sunday, teaming with former South African Liezel Huber for a 4-6 7-6 (5) 7-6 (3) victory over defending champions Vania King and Yaroslava Shedova.