Jelena Jankovic of Serbia defeated Russian fourth seed Elena Dementieva in straight sets to reach her first Grand Slam semi-final before the showers hit at 1:35pm (1735 GMT) forcing the others off the court and into the locker-rooms. Play was officially called off at 7:40 pm local time.

Russian seventh seed Nikolay Davydenko was two sets to one up (6-1, 5-7, 6-3) against Britain's Andy Murray in a fourth round tie while another Russian, Marat Safin, was 2-1 up in the first set against Germany's Tommy Haas.

With weather forecasters calling for continued showers overnight the remainder of the day programme and the evening schedule featuring top seed Roger Federer was also postponed.

Federer was slated to play world number 79 Marc Gicquel of France on the main Arthur Ashe Stadium.

But the bad weather certainly didn't dampen the spirits of 19-year-old Jankovic who was bubbling with excitement after her stunning upset of 2004 finalist Elena Dementieva of Russia 6-2, 6-1.

The 19-year-old Jankovic fashioned her third-straight win over a top 10 player and was so busy celebrating she said couldn't even remember the final score.

"What was the score? I don't even know the total score," Jankovic said. "It's amazing. She beat me in Los Angeles. We played for 2 1/2 hours and it was a tough match. I was expecting to have a tough battle. I don't know what happened."It was the second-straight upset in as many days for Jankovic who looked nothing like the player who dropped nine straight matches between January and May.

"I am happy I pulled it through," Jankovic said. "I'm so excited to be in the semi-finals.

"I played solid, didn't allow her to play her game. I was also returning well."In fact, Dementieva looked like the lost soul out on the Arthur Ashe Stadium as she couldn't overcome her poor serving and a rash of errors in the 62-minute match.

Dementieva, the runner-up at Flushing Meadows and in the French Open two years ago, had five double faults and 39 unforced errors.

"I am disappointed," Dementieva said. "I'm getting older and I haven't won a Grand Slam. That's what I am thinking about all the time. I feel like I was in good shape here. That's why it is sad."Jankovic, the 15th seed from Serbia, will meet one of two former champions Lindsay Davenport (1998) or Justine Henin-Hardenne (2003) for a place in the final.

Jankovic reached the quarter-finals by dismantling former champion Svetlana Kuznetsova 6-7 (5/7), 6-3, 6-2.

She also stunned Czech ninth seed Nicole Vaidisova 5-7, 6-3, 6-2 in the third round and is now headed for the biggest payday of her career since making her tour debut five years ago in Indian Wells, California.

The heavily-favoured Federer will have at least one more day of waiting before squaring off against Gicquel as he bids to become the first player in the Open Era to complete the Wimbledon-US Open sweep for the third consecutive year.

Top talents Henin-Hardenne and Davenport also had their match postponed.

Henin-Hardenne will be showing off her new game and renewing an old rivalry with another former champion Davenport, the 10th seed who has struggled with back and shoulder problems this year.

The Belgian won 19 of 20 points at the net in overpowering Israel's Shahar Peer 6-1, 6-0 on Monday. Henin-Hardenne sees the serve and volley game as the route she will have to take if she wants to extend her career.

"It is going to be the kind of game I will have to play in the next few years if I want to stay on the tour a couple more years," the second seed Henin-Hardenne said.

"I am not as tall, I'm not as strong as the other players. I save more energy to play like this."