Are you ready for a 'Grand' get-together at US Open?

Serena Williams and friend Caroline Wozniacki arranged a get-together in the US Open women's final, winning their Friday semi-finals in contrasting fashion on a stifling hot, humid day at Flushing Meadows.

"She's a good friend of mine," said former World No 1 Wozniacki, whose gaping hole in her resume remains the lack of a Grand Slam title.

"We were saying when the tournament started, 'We're in separate sides of the drawing, so hopefully we can meet in the finals. It would be great if that were to happen.'"

Williams said she had the same thought when the draw was made.

"She obviously wants to win and go for her first Grand Slam, and I want to win and try to make a little history," said Williams, who wants to end a disappointing Grand Slam season on a happy note by claiming her 18th Slam singles to tie Chris Evert and Martina Navratilova for fourth on the all-time list.

‘I would love to have a Grand Slam under my belt’

Friendship will be set aside in Sunday's final between the players who earlier this year spent a beach holiday together in Miami with some serious chips on the line.

"I'm in the finals, which is obviously great," said Wozniacki, who lost the 2009 final to Kim Clijsters. "It's been five years for me since my last one here, so I'm extremely happy to be back.

"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.

"The friendship, while we are on court, is put aside. We are both competitors," added the Dane. After the match, one of us is going to congratulate the other and we're going to be friends again."

Williams was in agreement.

"Regardless, I’m going to be happy with the outcome," she said.

Top-seeded World No 1 Williams overpowered Russian left-hander Ekaterina Makarova 6-1, 6-3, unleashing her daunting firepower against the 17th-seeded Russian.

Wozniacki advanced when China's Peng Shuai broke down in scary distress due to heat illness and retired in the second set, while trailing 7-6(1), 4-3.

Scary moments

The opening semi-final produced some scary moments as China's Peng fell victim to the severe conditions during an energy-draining, groundstroke battle with Wozniacki.

The match was still very much in doubt with Wozniacki serving at 4-3 and facing break point when the unseeded Peng suddenly grabbed her thighs and stumbled to the back wall of the centre court with what appeared to be severe cramping.

In obvious distress, the 28-year-old doubles specialist was eventually helped off the court to be evaluated by doctors.

A valiant Peng, playing her first career grand slam singles semi-final, refused to quit and returned in 11 minutes after a medical examination.

Six points later, Peng curled up in agony on the baseline, and officials called the match and Peng was lifted into a wheelchair and taken from the court to a standing ovation after the abbreviated two hour four minute battle.

"The doctor, she said to me, 'You are not able really go out to fight, compete, because look is not really well,'" Peng said about the medical evaluation when she met reporters after two hours of treatment.

"I said, 'No, no, no, I don't want to give up. I want to try one more time,'" added Peng. "And then I come back.'"

Speedy advance

Williams, the two-time defending champion, came on the centre court next and seemed determined to spend as little time as possible in the heat and succeeded, trouncing Makarova in 60 minutes.

The American blasted 24 winners, including five aces. Makarova hit six.

"I'm just really excited to be in the final. In the beginning of the week I definitely wasn't sure I would make it this long. So I'm just elated," said Williams, who failed to reach the quarters in any of the year's previous three slams.

Makarova, playing in her first slam singles semi-final, praised the victor. "Serena, she's a great, unbelievable player. Today she was so aggressive."