When Serena Williams takes on world No 1 Victoria Azarenka in the final of the US Open today, the all-conquering American will have more than tennis matters to fret about.

In her past two visits to Flushing Meadows, the world No 4 has lost her mind and with it her chances of the title. So far this fortnight, she has kept her temper in check and her game has been in smooth working order.

In 2009, Williams lost her rag with a foot-fault judge who said she had overstepped the line on a second serve late in her semi-final match with Kim Clijsters.

The double fault gave Clijsters match point but Williams compounded her error with an expletive-laden tirade that prompted a point penalty: the match went to the Belgian.

Having missed the 2010 US Open because of injury and illness, Williams returned in 2011 and looked the likely champion. Then she exploded in the final against Sam Stosur when a call of hindrance went against her, after she yelled out before Stosur had tried to get a racket on the ball.

In the build-up to the event, Williams admitted that for whatever reason "things seemed to go wrong in New York".

To add to Williams' nerves, the women's final was delayed until today due to horrendous weather in the New York area, including a tornado touching down three miles from Flushing Meadows.

"My goal this year was not to get in any fights, but something happens, then, oh, you know, I try to count to 10," she said. "Hopefully I can make it."

Certainly it has worked so far, and there seems no reason for her not to repeat her triumph over Azarenka from the semi-finals at the Olympics.

She has been utterly ruthless en route to the final, reaching it without dropping a set and without dropping more than four games in a set.

The three-times champion, appearing in the final for the sixth time, won Wimbledon and the Olympics this summer and her confidence could not be higher, particularly as she has won nine of her 10 meetings with Azarenka.

But though Williams is the overwhelming favourite, she still attempted to take some of the pressure off her shoulders. "I don't have anything to lose," she said. "I feel like I'm going up against the most consistent and the best player this year. It will be a good challenge for me.

Azarenka has been almost as equally impressive in reaching the final for the loss of just one set, to Maria Sharapova in the semi-finals, a match in which she showed the kind of form that took her to the Australian Open title in January, her first Grand Slam crown.

The Belarussian is perhaps as well known for high-pitched shrieking during points as for her tennis, which can be outstanding. It rarely goes down well with the crowd, who have been known to jeer her.

Her attitude can come across as cocky, but she is at her best on hard courts and is well aware that her head-to-head record against Williams means good will not be enough in the final. She has to be virtually perfect.

"I definitely need to find something to surprise her because she's in great form and feeling really confident right now," Azarenka said. "She has everything on her side.

"With Serena it's not really the long rallies. It's all about who grabs the first opportunity, who is more brave to step it up right from the beginning.

"I've got to do something different because the other times didn't really work for me. I definitely have to try to make sure I'm the one who dictates the play and try to control the match."

Barring another meltdown, that is likely to be easier said than done.