Caroline Wozniacki, Vera Zvonareva win

NEW YORK -- Clearly, Caroline Wozniacki has learned one thing about making it big in the Big Apple: When The Donald asks for something, best to say yes.

The top-seeded player at the U.S. Open advanced to the semifinals Wednesday night with a 6-2, 7-5 victory over Dominika Cibulkova, a match Donald Trump watched from Wozniacki's player-guest box instead of his usual suite.

"He called my agent and asked if there was going to be a space in my box," Wozniacki said. "I said, 'Of course, there's always a place for Mr. Trump.'"

Wind gusted up to 34 mph and played havoc with Wozniacki's shots -- to say nothing of Trump's hair.

A messy, mussy night that included 43 unforced errors by the loser, which plays right into Wozniacki's way of winning. She gets more balls back than anyone on tour these days. Her first five opponents have averaged 33 unforced errors.

"It felt like we were playing in a hurricane or something," Wozniacki said. "But it was the same for both players. I'm happy to get through."

Midway through the second set, the generally unflappable Wozniacki got into an extended discussion with chair umpire Anthony Nimmons over a ruling that a point should be replayed. Cibulkova served and Wozniacki's return landed near the baseline; Cibulkova's subsequent forehand went out. But a line judge had called Wozniacki's return out before correcting that call.

Nimmons decided that that changed call affected Cibulkova.

Wozniacki approached the chair and asked, "How can you replay the point?"

Nimmons replied, "In my eyes, she was hindered by him."

To which Wozniacki responded, "You've got to be kidding me," a phrase she would repeat as the argument continued.

Eventually, the point was replayed, and Cibulkova won it and that game, part of a tight, tense set.

Her semifinal match is Friday against No. 7 Vera Zvonareva, a 6-3, 7-5 winner over No. 31 Kaia Kanepi.

The 31st-seeded Kanepi struggled on a gusty afternoon in Arthur Ashe Stadium. She hit only 18 winners to go with her 60 unforced errors.

"The weather was definitely not for the good tennis out there," Zvonareva said. "But no matter what match had to be played, we were both trying our best."

The tone for the match was set early, when the players traded service breaks right away to make it 1-1, and they combined for 12 unforced errors and one winner through the first two games.

Asked how much she could blame on the wind and how much on her own play, Kanepi said, "Well, 50-50, I think."

"I think I can't blame the wind for everything," she said. "I didn't play well. Vera obviously played very well."

Zvonareva, known as one of the more temperamental players on the tour, had a mini-meltdown here last year in a fourth-round loss to Flavia Pennetta and then afterward insisted she didn't lose her temper.

"That match is in the past, but I learn from every match," Zvonareva said when asked about last year's performance.

The first women's semifinal was set up Tuesday, when a pair of two-time winners at Flushing Meadows, No. 2 Kim Clijsters and No. 3 Venus Williams, each won.

Information from The Associated Press was used in this report.