Wozniacki, Serena to clash in semis; Zvonareva falls at U.S. Open

World No. 1 Caroline Wozniacki time champion Serena Williams cruised into the semifinals, while up Vera Zvonareva succumbed to Aussie Samantha Stosur in Thursday's women's quarterfinal action at the U.S. Open. Wozniacki and Williams will do battle in a marquee semifinal here on Saturday night.

After rain wreaked havoc in New York the previous two days, the women finally returned to the courts at the USTA Billie Jean King National Tennis Center for the first time since Monday.

The 2009 U.S. Open runner-up Wozniacki got past 10th-seeded German Andrea Petkovic 6-1, 7-6 (7-5) on a 584-seat Court 13, which became a court option on Thursday when an issue surfaced with the court at Armstrong Stadium, the second-biggest show court on the grounds.

Wozniacki moved on in 1 hour, 40 minutes, including a hard-fought 73-minute second set. The popular Dane broke Petkovic six times, compared to three breaks for the German loser.

"I'm just happy to be in the semifinals once again here," Wozniacki said. "A little bit of different conditions today compared to what I've been used to. You know, today I was just, it was just to get through, basically."

Petkovic, who will turn 24 on Friday, reached the quarterfinals at three of the four Grand Slam events this year, her best-ever one on the WTA circuit.

The 21-year-old Wozniacki, meanwhile, will meet Williams for a third time, all on hardcourts, seeking a first-ever win. The two stars haven't met since the 2009 season.

"I think Caroline is a very consistent player," Williams said. "I think both consistent on the court and then consistent in playing tournaments and doing well and winning tournaments as well as going really far in tournaments. That's pretty much what it takes to be the best."

A 28th-seeded Williams handled 17th-seeded Russian Anastasia Pavlyuchenkova 7-5, 6-1 at Arthur Ashe Stadium, as the bout came to a close when the American great fired her seventh ace of the day.

Williams advanced in 1 hour, 19 minutes with the help of six aces among her 26 winners. The powerful star broke the young Russian six times and Pavlyuchenkova piled up 31 unforced errors en route to the predictable defeat.

The 29-year-old Williams is a 13-time major titlist, including a trio of U.S. Open victories. She also posted a runner-up finish to her older sister Venus here in Flushing 10 years ago.

Serena is currently riding a 17-match overall winning streak, all on hardcourts, which includes titles in Stanford and Toronto.

If Serena can title here this weekend she would pocket $2.8 million, which would include a $1 million bonus for capturing this summer's U.S. Open Series.

She'll appear in her sixth career U.S. Open semifinal (4-1).

Meanwhile, a ninth-seeded Stosur beat the second-seeded Russian Zvonareva for an eighth straight time, as the Aussie posted a comprehensive 6-3, 6-3 victory in 67 minutes on the Grandstand court. Stosur fired 25 winners, compared to only nine for the Russian on Day 11, and Zvonareva was unable to break her big-serving Aussie counterpart.

"When you're playing well, it just kind of flows," said a happy Stosur. "You step up to the line and you play the next point and the next one and the next one. Happy to close it out in straight sets."

Stosur was last year's French Open runner-up, while Zvonareva lost in last year's U.S. Open and Wimbledon finals. Zvonareva gave way to Belgian star Kim Clijsters in a lopsided finale last year in Flushing.

The 27-year-old Stosur will now appear in her third career Grand Slam semifinal and her first-ever U.S. Open semi. She'll be opposed by upstart 92nd-ranked German Angelique Kerber on Saturday.

The 23-year-old left-handed Kerber will appear in her first career Grand Slam semifinal after upending 26th-seeded Italian Flavia Pennetta 6-4, 4-6, 6-3 on Thursday.

Stosur and Kerber have never met on court.

The women's semis were originally scheduled to be played on Friday, but because of the backlog of matches brought on by this week's wet weather, the women's final four has been shifted to Saturday night. And the original Saturday night final has been moved to 4:00 p.m. EDT Sunday.