By Larry Fine
NEW YORK (Reuters) - Caroline Wozniacki used her aggressive groundstroke game to near perfection on Tuesday and pummeled Italy's Sara Errani 6-0 6-1 to reach the semi-finals of the U.S. Open.The 10th seed reached the last four at a grand slam for the first time since 2011 by beating Errani at her own strategy, engaging in long baseline rallies but using superior power to open the court and find lanes for winners.
Dane Wozniacki walloped winners of all varieties, belting 26 of them to just 12 for her Italian opponent, who looked dazed and confused at times on court.
The match ended when an Errani forehand hit the net tape and flopped back on her own side of the net and the strains of "Sweet Caroline" began to serenade Wozniacki over the loudspeaker.
"It's been a pretty up and down year for me," said Wozniacki, whose two-year relationship with world number one golfer Rory McIlroy ended this year just days after their wedding invitations were sent out.
"To be here in the semi-finals of the U.S. Open once again is an incredible feeling. Definitely, hard work pays off. I'm here and I'm so happy."
The match began inauspiciously for Wozniacki, who struggled with the warm winds that blew through the stadium.
She hit an ugly double fault on her second serve of the opening game and had to fend off four break points to hold serve.
"Love-40 isn't really a good start, but it was really windy and it just took me a few serves to kind of get into the rhythm and figure out where to throw the ball and what to aim for," she said.
Wozniacki did not take long to adjust and ended up winning 57 points to a mere 26 for the overmatched Errani.
Errani, accustomed to keeping the ball in play long enough to profit from an unforced error, tried to force the action by approaching the net, but Wozniacki whistled winners over her, past her and occasionally right at her.
Errani came to net 20 times and won only half those points.
"She is much stronger than me physically. I think that was the most important difference today," said the 13th seed. "She don't miss a ball.
"I tried to change my game in the second set and come more to the net. I was trying but was difficult."
Wozniacki, a finalist at the 2009 U.S. Open, reigned for 67 weeks as number one back in 2010 and 2011 but is still seeking her first grand slam crown.
Standing in her path to a return to a slam final is China's unseeded Peng Shuai, who was equally impressive in routing 17-year-old Swiss Belinda Bencic in the lower half of the women's draw where the leading seeds have vanished in upsets.
"She's been playing well. She's playing aggressively," Wozniacki said of Peng, who has lost in their last five meetings while winning one set.
"She's strong from both sides. She's been serving well. It's going to be a difficult match."
"But it's going to fun," added a smiling Wozniacki, happy to be back on the main stage with a real shot at a major title.
(Reporting by Larry Fine; Editing by Nick Mulvenney)