When Serena Williams and Caroline Wozniacki examined the draw for the US Open, they joked about how nice it would be to play each other in the final.

Today, their joke becomes a reality as they vie for the last Grand-Slam title of the year.

The pair have forged a strong friendship over the past 12 months, turning to each other for consolation after their respective problems, sharing some beach time in Miami after Wimbledon where they even gate-crashed a wedding on the sand.

For Williams it was the perfect way to get over her bizarre exit from Wimbledon, when she looked dizzy and could barely stand up in her doubles match; for Wozniacki it was the ideal way to clear her mind after golfer Rory McIlroy had broken off their engagement a few months before.

In the past couple of months, their friendship has been tested on the court with meetings in Montreal and Toronto, where Williams scraped through in three sets.

Today's final offers both women the chance of glory, with world No 1 Williams going for her 18th career Grand Slam while victory for Wozniacki would mean a first Grand-Slam title, five years after her only other final, having been written off by just about everyone as a contender for the sport's top titles in recent years.

It has been an up and down year for Williams. The American has won five titles but did not make it past round four in any of the other three Grand Slams, including a Wimbledon exit that had many questioning what was going on.

"I worked really hard for Wimbledon," Williams said. "I worked really, really hard, and I was really disappointed and sad and shocked that I wasn't able to win. I worked hours, more than I worked before. Maybe it's just paying off now."

Her 18th Grand-Slam singles title would put the 32-year-old alongside Chris Evert and Martina Navratilova in joint third in the all-time list. It's something she doesn't want to miss out on, however friendly she and Wozniacki have become.

"It would be hard for me to imagine that I would be happy losing," she said. "I won't be. But I am just elated to be in the final again.

"[If I lose], in 10 years from now it won't be: 'Man, I'm still sad about it'. I have accomplished a lot so I think I should be happy about that. And I am. When I look at the big picture like that, that helps me. That's the part that helps me to be able to relax and not take it so serious."

The American has not lost a set on her way to the final and not dropped more than three games in a set but she expects a tough battle in today's final, with so much on the line.

"I definitely expect another close match," she said. "She really knows my game well and knows how to play. She's so consistent. I think that's one of the things that makes her really tough. So I just have to be ready for that and, again, just stay calm and be able to relax and be happy."

When Wozniacki reached the final here in 2009, she was just 19 and was outplayed by Kim Clijsters. This time, after everything that's gone in between, the Dane believes she is ready.

"This time it's going to be different," she said. "I hope that I'll go out there and just go for it. I have nothing to lose.

"The last two times I played Serena we played two really tough three-set matches. Either way, it's been a great tournament for me and I hope that I can get one more win under my belt."

But having surprised everyone, not least Maria Sharapova in the fourth round, by playing some of her best tennis in years to get to the final, Wozniacki is allowing herself to dream.

"It would mean so much to me. I would love to win it and have a Grand Slam under my belt. It would definitely have the media stop talking about my lack of a Grand Slam, so that would be nice."